Years of experiance to start with. There is seldom any parts that will actually make you any faster, its the knowledge of bringing out the best of it that is the most important I think. Assembling an engine right, having the ear to adjusting it right, run-in etc, etc. And propobly the #1 on the go-fast list is driving and setting the car up so you'll allow the engine to show. Slow in a corner - slow at the straight, fast in a corner... you get the picture.
A boost bottle (or whatever gizmo) wont compensate for that of course.
Just so there is no missunderstanding, at the euros in Portugal '03, our engine was not any faster then anyone elses I think either. Even though it was a huge track it was'nt a motor-track so to speak. You had to have an easy to drive car so you could keep up the corner speed and make it run for the whole heat (or final) without running out of fuel or get vapoor lock etc. In that deparment we failed...
