PhatBox for my 93' S4?

[Ivan Demkovitch]

Got a link from my friend for what appears to be a good deal on PhatNoise:

http://forums.slickdeals.net/showthread.php?threadid=92789

I'd like to have it in my car, but not sure if I can integrate it with my 
sound.
I got 10 disc CD Changer and wonder if I can replace it with unit above.

At manufacturer website they have instructions on Audi cars starting from 
1998.

Is there any other MP3 options for my S4?

Thanks!
Ivan