I would suggest it would work in the same priciple as the Louts Challenge thing did a few years ago. If you aren't fimiliar with that what they did was they offered a chance where you could pay $X (can't remember but was about $3K) at 3 different state venues for a competition in either the Lotus Elise or the Exige Cup cars (was more $$$ for the Exige one obviously). During the day they had 6 cars and the competition was such that over the weekend you had to drive in all 6 cars with I think the combined best time from all of the cars you drove determining the winner. The top 5 from each state went off to a finals thing and the winner in each class (Elise and Exige) got a fully paid for drive in the Lotus Cup challenge the next year.
But my bet would be that if there were X number of cars you would have to rotate through all of the cars, rather than just using the same one for the whole competition to make sure there were no "his car is faster than mine" cry babies.