You have no choice to put the pedal to the metal on both runs and both cars needs to be different. What would you choose?
Uphill: Hennessey Venom GT! It's the fastest car in world. I would fly over the finish line right at the end.
Downhill: An MX5. Yes, I'd jump the car I know the most and see how fast it can go with the help of gravity!
So what would you opponauts choose?