Yes it will void your warrently(most likely). Dealers can detect the chip but some are chip friendly and will work on your car w/ the warrenty to a certain extent. I woudlnt really recommend it unless your really willing to use it. What I mean is, do you track/autocross/race your audi or meet up with audi clubs? If not then dont do the chip. The chip will kill your turbo's literally. Within the next 10-20k miles you'll blow your turbo's out and cats from the high boost inscrease from the chip. If your really want the extra power go to AWE TUNING . COM and get the KO4 turbo kit. The allroad has the same ROCK SOLID engine as the RS4 and what the K04 kit is RS4 turbos and intercooler etc. Its a ROCK SOLID kit and an amazing package. It literally turns your engine into the stock 380+ hp RS4 engine for 4,000 plus install. Its basically factory turbo's out of a RS4, which fit directly on allroads and s4's(they have the same engine). Its 4 times the chip but 90 more hp and alot more engine life when compared to GIAC, APR and REVO etc. chips.

Chipped allroads/s4's net anywhere from 300 to 360 hp and they last about 10-20 k b4 the turbos go
K04 allroads or RS4 turbo'd allroads net from 380 to 520 hp and last as long as a base engine depending on your set up.
Also auto allroads can be set up with the K04 kit with proper auto tranny software.

If you want some more power but dont want to cut on engine life and dont want to spend the money for RS4 turbo kits then
you can go to AWETUNING.COM and get all sorts of things... Diverter valves, conforti intakes and full back exhaust. Add all that for maybe 1,500 and youll get a 25 hp gain.