But if the game is going to be realistic and authentic, you must be able to choose you manfacturers, brake parts, clutches, engines etc... all are chosseable IRL, and all manufacturers bring something different to the table, speed, aceeleration, longetivity, quick repair/replacement..... Would bring something completely different to the table, but for the sake of gameplay, racing exactly the same cars around is the way to go IMO, but if you go that far, you may as well take out the setups and only allow players to run the set the host chooses....