Definitely a rating system would be required in order to guarantee clean races. IMO this ratings should be accomplished by means of several official tests. Those tests would rate several things. Speed, consistency and cleanness. It could be more or less like Gran Turismo licenses. You could try each test as many times as you wanted but considering that the average result of the, let's say, latest 3 tests would be used. Some tests would be about speed other about consistency and others races against the AI. For sure official content with reviewed track limits should be used for the different tests. Like any license you should have to renew it, let's say every year, with new challenges Apart from creating a rating which could be useful for defining thresholds to be eligible for a race, it would add some competition within the community. For sure license minimum requirements could be set by the sever admin from none to very exigent.