I sold my A3 a few months back and I have some leftover car audio equipment:
Steering Wheel Controls:
PAC SWI-CAN2 (CANBUS interface) - http://imgur.com/Qj1q8
PAC SWI-JACK (Interfaces between CAN2 and radio) - http://imgur.com/fMEKa
$40 each -or- $70 for both.
Both are brand new, never used.
Scosche AU2392B Single-DIN Installation Kit - http://imgur.com/ntpXH
$15 - Brand new, never used.
Metra 40-EU55 - http://imgur.com/VE0F5
$15 - Used
Shipping is $8 per item, but if you buy three or more items shipping is free!
PM me if you're interested.