Icelink you can control through stereo or Ipod as well. The full detailed instructions as well as some tips and information are posted here.

https://www.audiforums.com/m_248226/tm.htm

I'm a newb, but im guessing The "best mods" question comes up alot, and ive found the best way to approch this is first figuring out what your goals are.. Autocross, Drag, Street.. etc. Esp if you wanna do autocross 'cause theyre classes are very defined and if you do just one mod too many, youll be out calssed. anyways good luck.

SilverS4, Just wanted to say welcome... the converter oshburg mentioned you can get just about anywhere ie: Best Buy, Circuit City, Radio Shack! They work pretty well if you really want to retain the use of your stock radio and they are simple to hook up, but sounds quality of a aftermarket HU will always be better!!!

Oh yeah be prepared to get a whole lot of responses like "search" "read the stickys" no matter how much yousearched. The "Forum *****" will tell you that everything has been discussed here about every audi!!! And usually they are right about that!!! Good luck!