I got a couple of ideas how old IV races (when your car wouldn't fix itself) could work again, and maybe this could be a separate mode.
1. Combining IV and SK. In GTA IV online races, there's traffic, so if your car gets totaled you can get another one. We could make it so that there are parked cars on the side of the road like in SK races, and you could just get a new one.
2. Combining IV and Mario Kart races. Just put pickups that would fix your car.
Or maybe even a combination of the three modes, if that's possible.