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1999-2005 BMW 3 Series sedan

How to upgrade the stereo system in your 3 Series sedan

1999-2006 BMW 3 series sedan

In brief: This Crutchfield Research Garage article gives you an overview of your BMW's stock stereo system and your aftermarket upgrade options. We'll tell you all about:

Then, use our vehicle selector to find the gear that will fit your BMW 3 Series.

Overview of the BMW 3 Series sedan

The BMW 3 Series has changed a lot over the years, but it's never lost that certain something that makes it, for many, the finest sports/luxury car in the world. That's why almost any car magazine's annual "top ten" or "best of" list almost automatically includes a 3 Series. It's kind of become a cliché, but hey, the car really is that good. A lot of manufacturers have tried to imitate and improve upon the 3's all-around excellence, but few have succeeded for long.

The fourth generation 3, known internally and to serious BMW fans as the E46, was, like its forebears, a wonderful combination of comfort, power, and driving feel. In sedan form, it's totally capable of hauling the family, but it's also happy to haul something else when Mom or Dad finds a curvy stretch of road. The styling, a somewhat controversial subject back in the day, has aged remarkably well, and the interior remains a comfortable, well-designed workplace for serious drivers and their lucky passengers.

BMW 3 Series radio

The 3's base radio was somewhat pedestrian (Crutchfield Research Photo)

The factory stereo system

As wonderful as the driving experience might be in a 3 Series sedan, the audio experience was less enthralling. We've seen the stock systems described as "muffled," which is not exactly what you want in a stereo. Muffled or not, the receiver and speakers are still aging rapidly, so if you're serious about sound, you'll want to replace them.

The standard factory system consisted of a BMW-branded AM/FM/CD receiver (or cassette, in early models) and ten speakers. The optional 12-speaker Harman Kardon system used the same radio, but added better speakers and a subwoofer. A trunk-mounted CD changer was another audio option.

A trunk-mounted CD (later DVD)-based navigation system was also available on the 3 Series, and the route information was displayed on a variety of receivers with ever-larger screens over the years.

BMW 3 Series nav receiver

Replacing the factory nav unit is not a job for the average DIY-er (Crutchfield Research Photo)

Removing the factory radio

You’ll face different installation scenarios, depending on which factory system you have. The standard radio is no big deal. The Harman Kardon system adds a little twist. The navigation system is a potential deal breaker.

We’ll discuss all three situations below, but the best solution for these systems is a complete system overhaul — replacing the receiver, factory amp(s) and speakers. If speaker-only replacement is your best option, look for aftermarket speakers with an impedance equal to or greater than that of the factory speakers.

Standard stereo system

Replacing your car's standard "BMW Business" receiver with a single-DIN (2" tall) receiver is a bit of a challenge, but it's thoroughly within the capabilities of most DIY-oriented car owners. There's a bit of trimming and adjusting to be done, but other than that, this is a straightforward project.

Installing a receiver with a fold-down face might seem like a good idea, but the screen will block the center dash vents, so we don't recommend it. The good news is that iDrive had yet to trickle down to the 3 Series, so upgrading this model's factory audio system is much easier than it is on later 3's.

BMW 3 series dash kit single-DIN

You'll need this dash kit to install a new receiver in your BMW

We'll detail all the disassembly information in your Crutchfield MasterSheet, of course, and we'll give you a nice discount on the dash kit ans wiring harness adapter you'll need for installation.

If you have questions before you order, give us a call and let our expert advisors help you find the gear you need. After the sale, you'll have access to our Tech Support team for the lifetime of your gear.

Harman Kardon system

When you replace the radio in a Harman Kardon-equipped car, you’ll also need a special adapter called a line output converter. That's because the factory amplifier requires a low-level signal from the new radio.

When you purchase your new stereo from Crutchfield, we’ll make sure you get all of the installation gear you need (mounting kit, wiring harness, antenna adapter, AND this line output converter) and give you a deep discount on them.

Stereo with factory navigation system

Replacing the navigation system’s radio is not something to undertake lightly. It requires extensive modification. You’ll have to fabricate a custom mounting kit, because there aren’t any ready-made aftermarket kits available. You’ll also have to extend the wires from the wiring harness all the way to the trunk where the car’s tuner/amp module is located. That means running those new wires all the way through the length of the car.

This is not a job for the average do-it-yourselfer and we don't recommend trying it. That said, if you have tried it already, feel free to share your trials, tribulations, and successes in the comments below. We'd love to hear from you, and we're sure your fellow owners will, too.

Tools needed: See MasterSheet for details

Read our Car Stereo Buying Guide for shopping tips and advice.

Shop for car stereos that fit your BMW 3 Series

Steering wheel audio controls

It's relatively easy to retain your BMW's steering wheel audio controls when you install a new stereo. When you enter your vehicle information, our database will choose the adapter you need to make your factory steering wheel controls work with your new receiver.

BMW 3-series sedan front door

The 3's front doors are reasonably easy to work with (Crutchfield Research Photo)

Removing the factory speakers

The 3 Series sedan has speakers in the front doors, rear doors, and rear deck. The Harman Kardon system adds a couple of small woofers on the underside of the rear deck.

Front door speakers

The front door speaker array consists of woofers at the bottom of the door, mid-range speakers in (fittingly) the middle of the door panels, and 1-1/2" tweeters in the sail panels. The crossover points for the system are not known (by us, anyway) at this time. If you know, please share your knowledge in the Comments section below!

The woofer can be replaced with 5-1/4" or 6-1/2" speakers with the help of mounting brackets that are included with your Crutchfield speaker purchase. The 2-1/2" mid-range speakers are mounted in the grille, which is attached to the door panel itself.

Same-size replacements are not available, but smaller speakers can be secured in this space with the help of a universal backstrap. A wiring harness is not available for this location, so you'll have to splice, solder, or (better, easier idea) use a set of Posi-Products speaker connectors.

Getting to the woofer and the mid involves removing the door panel. This is relatively light duty, requiring little more than some panel and Torx screw removal. There is a bit of a difference between the two doors, though, since the power mirror switch assembly is located on the driver's side. The passenger's side has a blank panel in that space. Both can be removed with a panel tool.

Detailed, illustrated instructions for this disassembly process can be found in the instructions that are included free with your stereo or speaker purchase. The key element here is to work carefully and patiently when removing the plastic door panels.

BMW 3 series door tweeter

You'll need aftermarket brackets to install your new tweeters (Crutchfield Research Photo)


To remove the tweeters, you'll start by removing two retaining clips from the trim on the front edge of the door. Pull that edge trim out just enough to access the tweeter; then remove the Torx T30 screw that secures the tweeter/bracket assembly. Pull the tweeter out and cut the wires close to the terminal.

Obviously, having done that, you'll need some more Posi-Products to connect the new tweeter to the factory wiring. You'll also need a universal backstrap to secure the tweeter in place behind the sail panel.

Tools needed: Phillips screwdriver, small flat blade screwdriver, panel tool, Torx T30 driver, Torx T20 driver

BMW 3 series rear door speaker

The rear door speakers are mounted in the door panel (Crutchfield Research Photo)

Rear door speakers

With the low-end duties handled by the rear deck speakers (see below), BMW installed 2-1/2" component tweeters in the rear doors. They're easy to reach, but same-size replacements are not available and neither is a wiring harness.

These speakers are mounted in the door panel, so you'll need to remove the panel to replace them. As with the front doors, there's nothing terribly complicated going on here.

Your best bet here is to replace these and the rear deck speakers (see below) with a set of aftermarket component speakers. To install a slightly smaller component tweeter in this spot, you'll need a universal backstrap and Posi-Products connectors.

Tools needed: Panel tool, Torx T20 driver, small flat blade screwdriver

BMW 3 series rear deck speaker

The Harman Kardon system includes rear deck speakers (Crutchfield Research Photo)

Rear deck speakers

The two rear deck speakers are 6-3/4" component models can be replaced with a variety of aftermarket speakers. Speaker mounting brackets are included free, if needed.

These top-mount speakers are quite easy to reach and replace, but there is a bit of drilling involved. Start by prying up the rear speaker grille, then remove the foam ring around the speaker. Remove the three 8mm screws securing the speaker, then disconnect it and set it aside.

Use Posi-Products connectors to join the new speaker to the factory wiring, then secure it with the screws supplied. Test it out, make sure it works, then replace the grilles.

Tools needed: Panel tool, 8mm socket, ratchet, and extension

Read our Car Speakers Buying Guide for more information.

Shop for speakers that fit your BMW 3 Series

BMW 3 series factory sub

The Harman Kardon system also includes a deck-mounted subwoofer assembly (Crutchfield Research Photo)

Bass in your 3 Series

The Harman Kardon system adds two 6"x9" subwoofers in a plastic enclosure mounted to the underside of the rear deck between the speakers. To replace them, you'll first need to remove the enclosure from the trunk.

To do so, you'll remove four 8mm screws from the bottom of the enclosure; then pry down at the rear of the enclosure to release two plastic retaining clips. Pull the enclosure out and disconnect the amp harness to remove. Once that's out of the car, you'll remove four Torx T20 screws from each speaker.

You can replace these subs, which are powered by a sub amp behind the driver's side trunk trim, with a variety of same-size, 5-1/4" or 6-1/2" subs. A speaker adapter bracket is required for the smaller models, and it's included free with your speaker purchase. Though the enclosure is rather thin, the cavities in the deck will hold a good sized magnet, so you can choose from a good selection of subs.

If that's not quite enough bass for you, or your car wasn't equipped with factory subs, you have a variety of options for adding bass. If you're thinking about a component subwoofers in a box, your available space is 30"W x 17"H x 29"/36" D. It's not a vast space, but that's plenty of room for some serious bass power.

For those who need their car's trunk to haul more than car audio equipment, a powered sub will provide plenty of thump while still leaving room for real-world concerns like groceries and luggage.

Tools needed: Panel tool, 8mm socket, ratchet, and extension, Torx T-20 driver

Learn more about building a bass system in our Car Subwoofer Buying Guide.

BMW 3 series trunk

There's room for a small subwoofer back here (Crutchfield Research Photo)

Other options for your 3 Series

There are plenty of other ways to improve your 3 Series sedan. Here are some of the ways Crutchfield can help:

Add an amplifier

Adding an aftermarket amplifier will really help you get the most out of your new speakers. The 3-Series isn't short on cargo space, but if you still use it for family duties, a compact Class D amp would be the best choice. Learn more about adding amps to your system in our Car Amplifier Buying Guide.

Install some Dynamat

If you like your music as pure as your driving experience, hearing more stereo and less road noise is a good start. The Dynamat Xtreme Door Kit is the perfect way to seal in sound. This heavy-duty insulating material is easy to install, and it really makes a difference.

Improve your security

Installing a security system in your BMW isn't easy (security systems rarely are), but it's less complicated than it could be. Our Crutchfield Advisors can help figure out what you need to get the job done, but we usually recommend taking your car (and your new gear) to a professional installer.

Building your system

The BMW 3 Series sedan is a car that, depending on the project, can be either easy, hard, or almost impossible for the DIY car audio enthusiast.

In the case of nav-equipped cars, the amount of work and expense involved in replacing that receiver makes it a daunting task for many owners. Replacing it with a brand-new touchscreen receiver takes a lot of time, skill, and money. Replacing it with a used or NOS (new old stock) factory model is usually cheaper, but "caveat emptor." Besides, at this point, the "nav" portion of the receiver's functionality can be easily surpassed by almost any portable GPS and most smartphones.

On the flip side of that are cars equipped with the standard radio. Replacement is obviously a lot easier with these cars, but some owners don't want to disturb the smooth factory look of the dash by installing a new receiver.

In both cases, you can make your 3 Series sound a whole lot better without replacing the stock receiver. A new amplifier, new speakers, and a subwoofer can make a huge difference in sound quality, even if the factory receiver is still in place. If you rely on digital sources for your music, there are adapters that will plug into your receiver and let you enjoy music from your smartphone or MP3 player. Satellite radio fans can install compact tuners to gain access to great SiriusXM® programming.

In other words, there are a lot of ways to make your 3 Series sound as good as it drives. Visit our Car Showroom to see what one Crutchfield employee did to improve the sound in his E46 sedan.

Let's get started!

Ready to shop? Use our vehicle selector to find the gear that will fit your car or truck. If you have questions of your own, give us a shout via phone, chat, or email

  • Sedra L. Taylor from Cincinnati

    Posted on 9/14/2021

    I recently to a car audio shop here in Cincinnati , and I was told that I could not replace the factory installed reciever in my 2004 BMW 325CI . I was aslo told the best speakers would be Harmon and I agree thos ewere the facotry speakers. I would liek to know if I can replace the receiver ? and where to purchase factory speakers for my car? thanks

    Commenter image

    Jon Paul from Crutchfield

    on 9/14/2021

    Sedra, Um, you might want to get a second opinion on that... In most cases (unless you have the factory nav radio), you can replace the stereo. Speakers, too. When you enter your vehicle's info into our Outfit My Car tool, you'll see which stereos (and speakers) fit your car, plus the correct harness. If you have any questions, our expert advisors are available via phone or chat.
  • Nick Valletta from Houston

    Posted on 5/21/2020

    I replaced the factory stereo on my 2005 BMW 330XI with Harman Kardon speakers with a Sony XAV-5000 radio and used the Axxess ASWC-1 to retain factory steering wheel controls. I was able to map the volume up, volume down, next song, previous song, and call button to my Sony XAV-5000 radio. However, I recently did the same install on a 2006 BMW 330ci but can't map the call button steering wheel control. The other steering wheel control buttons still work. I think it's because this BMW had bluetooth built in, but the previous one did not. Any idea if I'll need to remove the OEM bluetooth system in order to get the call button on the steering wheel controls to work with the aftermarket radio?

    Commenter image

    Jon Paul from Crutchfield

    on 5/22/2020

    Nick, If you bought your gear from Crutchfield, you can call Tech Support for free help troubleshooting your system. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Check out our tech support page for details.
  • Chase Scott from Champaign IL

    Posted on 8/23/2019

    Jon. I purchased a pair of speakers (from Crutchfield) that were said to fit my car. Upon installing them, they produce very low volume muffled sound. Most the stock speakers are blown and I am having issue finding what speakers I can essentially replace them with. Can you help?

    Commenter image

    Jon Paul from Crutchfield

    on 8/23/2019

    Chase, With questions like that, it's always better to have a conversation with a real live human. Since you bought your gear from Crutchfield, you can rely on our Tech Support for free help troubleshooting your system. I'll forward your email to them, and someone will be in touch soon!
  • TJ from Norwalk, CT

    Posted on 7/7/2019

    Paul from Parrish - in response to your question. If maintaining the factory controls is important to you, you might be better off keeping the factory head unit and using a signal/line processor that will rebuild the main signal from the head unit (before feeding in to the amp). These processors join the signals from all of the lines, which are often a partial signal intended for the speaker it's going to, and outputs a line that is essentially the union of all input signals. I believe the HK System has 12 signals and you can get a signal processor that will handle all of them. I used a 6 channel processor because I only connected the front components and a sub to the amp. I had an E46 325xi that I installed a system in. I maintained the head unit and from the outside you could not tell anything had been done to it. I tapped in to the lines in the trunk, behind the drivers side wheel well. I was skeptical at first about using the head unit but in the end I was extremely impressed, and more importantly, extremely happy. It might not be quite as good as a new head unit would be but for me it was well worth being able to keep the car looking 100% stock. Good luck!

  • David from Harare

    Posted on 5/9/2019

    Hi What is the model name or part number for the radio in the 3rd pic in your article.

    Commenter image

    Jon Paul from Crutchfield

    on 5/9/2019

    David, That's a Phillips 9022-014-08232 receiver manufactured by Phillips for BMW. For more info, your best bet is probably a BMW owners' forum.
  • Commenter image

    Jon P. from Crutchfield

    Posted on 10/24/2018

    CJ, The new receiver will (almost always) have a clock of its own, and you can adjust that using the receiver menu. The clock in the instrument cluster can be set independently.

  • CJ from Columbus

    Posted on 10/22/2018

    What about the clock that is tied to the stereo receiver? Will it always say enter time once I switch to aftermarket?

  • Commenter image

    Jon Paulette from Crutchfield

    Posted on 4/30/2018

    Efe, Factory-to-factory swaps like that really aren't in our wheelhouse. You might find some helpful info on a BMW owners forum, though. Good luck!

  • efe

    Posted on 4/29/2018

    How easy is a straight swap of speakers from 2003 325ci (Harman Kardon system) to 2002 325i (standard). I don't intend to made any additional purchases.

  • Commenter image

    Jon Paulette from Crutchfield

    Posted on 11/14/2017

    Ryan, With questions like that, it's always better to have a conversation with a real live human. Give us a call and talk to one of our advisors. We can help you choose the right gear and give you the right advice on how to install it.

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