It would be totally cool to have one painted up to match Orange for the some day in the future MoPho jr
There is actually a really wild gravity race here in LA. They do it on one of the most treacherous roads here, called Tuna Canyon, it is very tight and twisty and has big drops off the side.
The car manufacturers get involved and make really high tech cars, that hit 60mph on the downhill
Here is the one made by Honda to resemble an old F1 car, it is tube frame, has full independent suspension, disk brakes etc
http://www.makikodesign.com/gravity/images/gravity_racers132.jpg
http://www.makikodesign.com/gravity/images/gravity_racers024.jpg
http://www.makikodesign.com/gravity/images/gravity_racers088.jpg
http://www.makikodesign.com/gravity/images/gravity_racers076.jpg