Hi, i just recently bought a 01 A4 1.8T and was looking to install a HU and system in it. Where can i buy a dash trim it, and harness? also when i was trying to look for a opening in the firewall i cant find one. Where do you people put the wires through? now if i dont get a HU which wire do i tap into to get power for the amp? thanx

Page brrman in the A4 forum on this. He should be able to help.

the hole in the fire wall you need to take the plastic covering off the battery off. you will see a rubber gromet on the firewall. thats your hole. if youre going to use the stock unit which i recommend, you need a line out conv. which is tapped off your speaker wires. anymore questions just post em.

much easier place is go through the ecu box bc the back of it opens up right into the cabin of the car. if u look for my pics i posted there is a guy that posted where u can get the backin plate for 50 bux. the thread is in the a4 forum