I still think drivers should remotely pilot cars with about half the mass of the current ones that wouldn't be designed around protecting an occupant. They could go 300+ mph and show us a new frontier in human driving skill. All the "too dangerous" racing technologies would be allowed, and the track would have loops and crazy features like a video game. There would be no restrictions on car design aside from size, weight, a 360 3d camera array, and a standard telemetry interface.