Even though I'm not in the WTC I did get a chance try the Porsche 918 at Road America. After about 40 laps my best I could do was a 1:49.002. After my failed attempt to top your time I tried the Lambo 640 at Road America and was a little more successful with a 1:47.575. Strange as this sounds I've had my new G27 wheel for 7 weeks now and I'm finally getting my lap times on par with the controller. With the wheel I finally learned to go slow in and fast out improves my lap times
(Edit) I think I just found out the fastest car for long tracks, I just did a 2:03 at SPA on my second lap ever in a non tuned Bugatti, can't wait to try it at Road America