OK, I need to finish the post I started with and did not complete. My reservations about there being a disparity between the bimmer and all others are based on the following. I run in GT2 with a 2280lb Nissan. I run against a Porsche GT3 Cup car at 2730. I ran this 05 with a stock 222hp engine. On the dyno, 204 RWHP. At Lime Rock we ran 57.3 and 57.7 respectively. He was faster. At LR you would expect us to be close. At Pocono 4 weeks later, as you would expect, he also was faster. But by a much larger margin as Pocono is basicly a double drag strip with an autocross course in the middle. He ran a 1.38.1 and I a 1.42.9. We went from .5 seconds apart to 4.8 seconds apart. Look at the numbers; 450 lbs - about 100 more RWHP - 4.8 seconds. Now the BMW 2850 - RX7 2680 are 170lbs apart. Say the BMW has 50 more HP. Do some extrapolation and the BMW should be about 3 seconds a lap faster than the RX7. But the RX7 has the lap record. Now I am assuming the same clockwise course configuration. A BMW with the driver sleeping should be able to best the RX7. Unless the other dynamic factors, such as air drag, rotational inertia about the about the mass centroid, ect... come into play. Now like I was saying, I do not see the smoking gun as others.
Chris Howard