It must be your driving, check what driver aids you have on. By default, mine has autobrake on which is extremely annoying. Otherwise, I think FM3 had the about same handling properties of FM2, which were great.
Salaam
I a have been playing Forza 3 for some time now , its a fun game as far as the car customization is concerned, but lacks the selection of cars ,
DLC packs, theres like 20 of them. I've had the game since last year and I have yet to download a DLC or feel a lack of cars that come with the game.
You have to remember that even though GT4 came with a billion cars, they weren't individually customizable to the level FM3 takes it to.
Anyway, I do agree that this level of customization is insanely good, the only drawback being that the vinyl layers have really low resolution to keep FPS down.