Well, I was curious, so I bought a P and I had an S. I took them apart and took a good look. The cranks are the same other than the turbo scoop. Its larger on the P. The Port work on the sleeve is also larger on the P. and the piston is a machined piston. Other than that, I don't see much of a difference. The timing is 2deg different too, but thats minor.
anybody else know?
Am I going back racing?...Hmmm.. Not anytime soon... But soon enough.