I have seen a lot of posts about hooking up MP3 players, mostly ipods. I have an Iriver mp3 player that I would like to interface with my 2003 A6 stock stereo. It has an in dash 6 disc changer. I would like to install my mp3 player without having to disconnect the CD changer and dont want to use a casset converter or an FM transmitter. Does my stock stereo have RCA outputs? Any suggestions would be great.

Have you looked at any of the aftermarket solutions which plug into the back of your headunit? USA Spec, Dice, Neo Prolink, etc?

I use the Dice in my 2001 A4, and it allows for passthrough. Check the compatibility though, and any caveats.

I'm kinda new here, but have experience with one of these devices, but dont want to get in trouble by posting links or anything. PM me if you want.