OK I just got a 1997 A4 Quattro. It just has the tape deck in it. It looks like its longer than most cd headunits. Can I get some speacial housing to make a aftermarket headunit fit?
The dealer said that they usually had a cd player in the back im assuming he was talking about a cd changer. Would it be cheaper to try to get the cd changer or just change headunits? Also the Drivers side door speaker and im assuming tweeter since its so small don't work and the passenger side rear speaker don't work. What sizes are they and how hard are they to get to. In the back from a quick glance it appeared there was no amp and the speakers were set up with drivers or something. I have a pair of kenwood 5.25's would they fit anywhere? Any advice on how to set up the sound system would be great thanks.

Yes there is a dash kit and a wiring harness that you can find at many good (independent) stereo shops. The only downside is that the kit kinda looks like a monkeys asshole. It snaps into place, not very clean in my opinion. If you want to make it look good, you can take the trimbezel out and fill in the extra area with duraglass sand and paint. This sucks but ends up looking sharp if you know what you are doing.

As far as the Kenwood 5.25" I think those should fit into the front doors with no problem, but I also remember that the A4 has a bose system that is incompatable with any aftermarket speaker system. Your best bet is to pull that Bose crap out and start from scratch. You might have to end up rewiring all of the speakers to run them off your aftermarket stereo, but in the end it will be worth it. Stock Sucks!!! Even Audi.

If you do have speaker problems, it usually isn't the speaker but the bose amplifiers that fail when they are about 10 years old. I know I am an instaler. I see this all of the time. The only real thing that you should do in this case is to replace all of the speakers and wire them directly to the deck. You might be able to do this yourself but for a deck and 4 speaker install, I would charge $250-350.

A changer is a really bad way to go especially if you are already having problems with the stock system. Get rid of it.