+1 to OP.
All have been said in this tread already. I have read all the answers from Gjon but fail to see how a ModID could be any better than a combined TrackID/CarID system. If the original thought with ModID was to make it easier for the user play online, then going with a TrackID/CarID will defiinitely bring me less trouble joining servers without missmatches and requiring to download new content. For league play it will not matter, but the casual player will need to update mods everytime he go for a game... it will be no more casual playing I'm afraid.