I really like the idea but I'D suggest one addition: Fuel is a very scarce resource in the world of FO. So why only bet money on it, when you could make having the required amount of fuel a second condition for entering a race. The same might be possible with replacement parts, etc. Maybe you could even be sponsored by other people with fuel and parts and so on, who then get a certain percentage of the price money. Or you could rent out advertising space to people who own shops in e the game and receive money, fuel and parts as payment.
Such a feature would certainly be nice. I really hope that something like that makes it into the final game.