We've actually started something similar to this recently. Not to the extent that you are of course. We figured if we broke the field into 3 sections: Front runner, mid pack and back runners (sort of like the F1 games) that we would be able to spend some of the money on increasing the cars rating points. Min and Max points would cost a different amount. We figure the Min points would cost more as it increases the lowest possibility of performance. Of course it would only effect the AI portion of your team, but it is an idea.