The 2.5L five takes aftermarket tuning exceptionally well: Stage 2 E85 flex-fuel setups commonly make 550-620+ hp, and owners report that kind of power without drama over tens of thousands of miles. The flip side is that many cars in the market are modified, so stock-versus-tuned condition is a key thing to establish.
A tuner's favorite — big, durable five-cylinder power
Audi RS3 (8V) · ownership-experience