dynamic difficulty now in forza motorsport 4. So as you are playing trough the game, as your beating the AI by a lot, the AI not only auto upgrade its car it also starts to get harder and harder and harder, until your finding the right match. And in a race like this the target number of cars to pass will change, in an autocross your target lap time will go down. So as your playing trough the career, its gonna find that right difficulty level. But you can still adjust the opponent difficulty when you change your assists.