Well, maybe when an IV race starts you could have a textdraw saying "RAMMING IS ALLOWED IN THIS RACE!". And its logic, its a DM race, you're given a gun which is not only used to defend your car, it can be used to eliminate others out of the race, like shooting out others' tires or even killing the driver, and thats kind of like ramming...Anyway, up to Rac3r to decide...