After reading this thread, it seems clear that you should look at the Kyosho Inferno GT cars. If you want to try to grow an on-road racing scene, they could be your best option.
We have a new track here in Tampa that opened towards the end of November. The typical 1/8 & 200mm nitro cars race there all the time, but the fastest growing class is the Kyosho Inferno GT Spec class.
These classes are starting up for them all across America for 2008 because of their very low entry cost, good looks, incredible durability, good speed and hi-fun factor.
The Kyosho Inferno GT could be the answer you are looking for too.