If you just got an Xbox 360 should you buy forza motorsport 3 or wait for forza motorsport 4

Forza motorsport 3 is a great game and i really enjoy it. I'm not sure when forza motorsport 4 is coming out so unless you know when it's coming out you should proabably get forza motorsport 3. It's mostly your choice because no one has played motorsport 4 yet. So no one can tell you how fun it is.