I just ran into this problem. I ordered a CD player from Crutchfield and they gave me the installation guide for the 2001 C series. I got the premium Bose upgrade which has the 10 speaker system, fiber-optic wiring, but no CD player?!? I looked at the Bose website for help. None. Called Crutchfield, the dealer, and then finally MBUSA. They told me the stereo is run throught the central computer which needs to be 'told' the CD player is installed. Even if you get the hardware installed, the CD player won't work with the steering wheel controls or the factory wiring until the computer is reprogrammed. In the end, I had to buy the CD changer from the dealer (and return the crutchfield one). The dealer gave me a price break on the changer which still ended up being $1100!! For a 6 disc changer too!! <br> If you have any luck installing an aftermarket unit let me know. I'm sure the computer module can be altered/hacked if you can find the correct interface. I'd like to install a MP3 changer later on so let me know how it all works out for you.