Check out http://www.eliteaudiosolutions.com

These guys specialize in high-end car audio, not that cheap crap at your local big box. If you want clean, crisp, and sweet sound, give these guys a call. They can do everyhting to your Audi from custom fabrication, hidden installs, ipod/iphone integration (bypassing the crappy Audi GUI), all without voiding any Audi warranties!! Not to mention, they keep your music completely digital!!

Sam and his team are the best hands down!! Nobody works on my Audi but EAS!!