Have you checked Italianspeed? My father and brother uses these for their Audi A3 and VW Passat and are very satisfied. I will buy one of those if I feel the need for speed in the future.been looking for some time at the below
although to be honest I cannot understand the prices, and I guess thats the reason I have not picked one yet.
on my older cars Ive always used re mapping to the ECU like super chips however they leave a tag on the file which if looking for the dealers can see although its doesn't say whats happened but they would use that if you needed a warranty job doing.