My observations imply that any downforce less than 40 have no effect on cornering speed, but, reduce straight line ACCELERATION. I'll do more testing to find solid proof, but, the cars with high aero and less power both seem sluggish. I think it could be fixed with even as little as 5-10 HP difference. The reason the Vette's fast is the pure acceleration. Once the rear tires hooked up, the car accelerated faster than all of the others-even the Audi @ 50/50 torque split. Just my findings.
I admit, I can't run qualification times like you guys, and my Vette lap was 1:45.8xx, BUT I still noticed the same drastic difference in lap times that james and others have as well.
So, we could make the other cars faster, or the Vette slower. I just have a pretty good idea of what will happen. I think it'll almost always be a Corvette walkout in qualification, and that the other cars will only pick up any slack left by the more powerful cars.