Years ago, we ran up South Mountain Road so fast that it confused our Garmin GPS. We were pulling close to a G in the turns and the GPS just showed us spirraling off into empty space. It was pretty funny!
These rallies are a great sport in a Cobra. You get maps and instructions at the registration and we drive some great twisty, scenic roads and find the checkpoints. You bring someone to ride with you and they use their wristwatch to count you down to the correct second to run your front tires over the hose. The car that hits times closest to zero, wins. There is a beginner class and an expert class so you don't compete with the experienced teams.
The best part is that you can drive whatever speed you want until you get to the checkpoint. On the back roads, that can be a LOT of fun! You get to see how your car performs compared with BMW's, Corvette's, EVO's and Subaru's. Those things are seriously fast on a twisty road.