Neat results with LapSim. I haven't used it. Does it assume some nominal wheel rate or something such that the "setup" changes the weight distribution? What does it use for grip/tires? More weight is going to need more tire, but we're limited by rim width. A 50:50 car has an advantage there.

And no has mentioned the Fiero. Which is an ITA car now. I think weight was added in it's transition from ITS. Are these 50 pounds in there? Or did the ITA classification come before the new process?