I stopped playing Forza 2 as soon as I realized that I just had to mod my car until it was waaaay faster than the other cars in any given race.
Did Forza 3 change anything in that area? Specifically, does it force you to only use cars in a certain range of performance?
Most (maybe all?) of the races in Forza single-player require you to match a certain type of vehicle. It may be limited to performance in some races (as defined by the letter classes), in other races it may be limited by make and/or model, in some it's even more granular -- I recall at least a few where there were horsepower limits, so you had to mod the car for weight and balance to get that edge.
I don't remember Forza 2 well enough to compare, but I felt that Forza 3 provided a good amount of challenge for most of the races. Of course, the make/model races were easy to overpower (I had a Stingray optimized for handling first and power second, and easily wiped up the Chevy meets). But overall, the balance was pretty decent in Forza 3.
I would say Forza 3 is even more loose in this department.
About half of the races in event list have very loose requirements (i.e. same engine type, same manufacturer).
The other half has restrictions on performance index with often additional restrictions on manufacturer country, and very few have limitations on pure horsepower or to be stock.
If Forza 2 didn't allow road cars in race classes (R4-R1), Forza 3 allows you to tune any car to any class, and you would see that R3 and R2 classes are dominated by tuned road cars in leaderboards (but nothing stupid like F class cars).
Personally I like modifying cars in Forza, it lets you make a lot of cars competitive. Forza 3 is a great game, if you like racing games then I don't see why wouldn't you enjoy it. It is not drastically different from Forza 2 though, so if you hated it then you probably would hate this one too.
