Please offer expertise on stereo upgrade

Long time listener, first time caller. My questions are regarding the stereo upgrade possibities. I want to upgrade the amp, speakers, and add a subwoofer. Here are my three questions:

1) I have read about knocking out the ski plate (non-ski bag 328i) for a subwoofer. With a direct opening into the trunk, doesn't this add more road noise when the car is put back to stock when I get ready to sell it (or just driving with the radio off for that matter)? Does this also lower resale value when the plate is permenantly knocked out?

2) Why would I need a LOC from my BMW head unit for an Alpine 5-channel amp if the stock amp is doing just fine with the lines from the stock head unit?

3) I will be putting MB Quarts up front (cutting the stock mid altogether), but should I leave the stock speakers in the back hooked up? Should I run them off the Alpine, or use the stock amp for the back speakers?

And overall, is leaving the stock head unit going to still sound crappy even after adding speakers, a sub, and a high quality amp?

Your thoughts, and more importantly, your first hand experience is appreciated!

Well, I just got done doing the same basic thing. TO answer your questions....


1) I don't hear any noticable difference with it being gone. I also doubt that would hurt resale value.

2) The reason you need a LOc with the stock HU is because the factory BMW radio uses a "balanced" signal. Most amplifiers (including Alpine) will not accept the balanced inputs direct. However, A/D/S/, Xtant and a few others do.

3) I kept the stock speakers in back powered by the stock amp at first. However, with good speakers up front, I noticed it sounded better without rear speakers. This is pure opinion of course


When I first did my stereo upgrade, I just did the amp, speakers and sub. Within 3 weeks of listening to it, I realized 2 things:

1. It sounded way better than before.
2. It needed a new head unit. Don't get me wrong, you can have a good setup with the stock deck, but I could tell something was missing. I just got an Eclipse head unit put in and the difference is night and day. I've had and loved a few Alpine's, and I think your findings would be similar.

SOrry for the long reply, but one word of caution. Be prepared for your radio reception to degrade a bit. Once I got the amp and sub installed I noticed it. Must be from interference from the amp, or the sub magnet.
Good Luck

1) Good chance that the buyer of your car will not even notice your plate being gone. Besides, it doesn't add to the road noise at all.

2) You find it'll be worth time and money to just go ahead and change everything out for best perf. Get an aftermarket HU plus aftermarket amp to power your aftermarket speakers.

You don't have to get a 4 channel amp to power front and rears, you can just run the rears off the head unit, but personally, I got a 4channel amp to power everything since I'm running Dobly digital surround sound from the PS2.

You'll find it that with the E46, you either go all out, or don't do it at all.

Does anyone have any pictures of what it looks like from the inside when you knock out a ski plate and add a subwoofer?

Also, if I have to switch out the head unit, does it have to be a high end unit to make a marked difference in sound quality from the head unit. I already have an Aiwa head unit ($140) and Aiwa six disc changer from a previous car. Is this too low end to make a difference?

This forum rocks because the experts who have actually done this reply!!

If you are running quarts, then I would get a better head unit. Just my $.02

It sounds like I need to do a complete swap out. THAT HURTS THE WALLET!

I would do it myself, but after reading the DIY guides, I don't think this is the same kind of deal as the old Chevy's I used to throw gear into. Who does good work in the DFW metroplex area?

Someone goofing around in my trunk doesn't bother me, but someone taking my doors apart has me a little nervous.

You really DON'T need to swap heads if you don't want to.

Here's why:

1) Find an amp that can accept balance inputs - typically these are top-of-the-line amps, which is important in its own right.

2) You will then be replacing your front stage w/ MBQuarts - that's actually really great. Those sound awesome.

3) Balanced input/outputs are actually a good thing - they typically pump out at a much higher voltage of power, and its grounded, so the signal going to the amp is much cleaner. This is why typically high-end amps have this capability. Very few head units kick out a balanced signal, so this is actually kinda nice.

4) Unless you are looking for video/sound processing (EQs, spatializers, timing, etc), or are looking for the head to control sources other than a CD changer, a new HU won't do much for sound. Most CD players use a 1-bit DAC to read CDs and convert those signals to sound. Only really high end stuff uses better DACS which then would "clean up" the sound. Actually it doesn't really clean up anything, if anything, it ensures what is on the CD is what you actually hear.

5) Head units should be based on functionality and interface. If all you want it to do is read CD's and send a signal to your amp - the stock head is actually more than fine.

agree with previous post. The standard BMW headunit isn't all that bad, people have to realise. I think that the desire of many members to swap out the headunit is to add a level of difference/coolness to their car or to increase the (I don't know the polite way of saying this) ****upability of the sound. By that I mean playing around with it, DSP setting, phase correction, etc, etc. It must be realised that being able to manipulate the sound coming out of ur headunit should not always be construed as a beneficial thing. The most high end of audiophile headunits and home audio amplifiers offer NO tone controls at all, let alone DSP, etc. It's a straight through path for the signal that will produce a sound most faithful to the sound on ur CD's. or tape's. But if u are a tape fan, you'll have to use a Nakamichi headunit! =)

By outputting a balanced signal the BMW headunit is in an elite group by itself already, as balanced signals are inherently better than unbalanced ones. Do a search on yahoo about it and u'll see why. of course, if u swap out the head unit then u wouldn't care less whether the signal is balanced or not, since u'll be able to buy to preference.

If u are concerned about ur radio reception just make sure you use cables that are shielded properly.

HaN-hAn