The real question is, what to do to complement the RS4 cylinder heads. My current thought is to shoot for something in the 550whp range on the smallest turbo I can manage to hit that goal with on pump 93 octane fuel and a water/methanol injection system.
![Audi B5 RS4 Cylinder Heads boxed up](https://myaudis4.com/wp-content/uploads/2013/11/rs4_heads2-1024x742.jpg)