The safety work all the auto racing sanctioning bodies (IRL, NASCAR, F1, etc.) do is incredible.  I guess when you have nearly unlimited budgets the engineers can come up with some pretty sophisticated vehicles.  I suppose with wieghts less then half  (~1524 lb for IRL) a street car the energies are lower than a street car at any given speed but the forces that must be dissipated are still incredible. 

Tony 

Never let a motorcycle take you somewhere your brain didn't go five seconds earlier.