Well, it'd work like a dream, but there's a few hang-ups: In Multiplayer, there are a lot of cars that show up for you, but none of the other players can see. That puts a kink in things because what you can't see, you can't figure out how to pass.
And if you wanted to, say, do a pit maneuver on the leader, maybe brake check the dips behind you, you cant. Because no matter what cars you use, when you go in for a door-shaver, your car passes through like it's Donny the Road-Raging ghost.
I guess this is to avoid hurt feelings, or keep from frying a server, but it does hamper things.
Maybe one day these flaws can be handled, but I can't say when.
Still, good idea, and it would be a good use for the game.