@Pixelchaser : polycount of physics mesh has no influence on the grip. It might be a tedious process but a test can be made on a straight plane: with only few verts and another with crazy amount of verts. Then with same car and same conditions test acceleration and brake distance. I'm 99.99% sure there would be no diferences. I would say however that a detailed (in micro bumps) track might convey better the sense of grip than a perfectly flat one because it would bring somr more life into the wheel. Regarding resolution no need to go overboard. Your pic is from an angle that makes it seem very dense but it not in reality. I'll be home in a couple of days and I'll post some samples with some sort of reference to real track dimensions.