The ultimate simulation racing game. If you want simulation, you want Forza 2.

User Rating: 9 | Forza Motorsport 2 X360
This is hands down the best simulation racer you could ask for. If you want the freedom to upgrade your car, paint your car, and tune your car, then this is your game. With an amazing library of vehicles there's plenty to customize and tune here. Online play is the best of any online racing game. The only complaints with this game come from small details. The lack of any changing weather or different temperatures, etc., leaves the racetracks feeling rather stagnant. Additionally, there are too few tracks within the game. Too often are there multiple variants of the same track to compensate for the lack of variety. Also, if you don't plan on playing online you'll probably find the offline career mode rather unrewarding. There's not much in the presentation, and career mode does come off a bit stale. However, those who want to sell cars on the auction house, participate in online tournaments and races, and build that perfect car will be occupied for a long time.