Forza Motorsport 3 Unlockable Help?

I just got Forza Motorsport 3 on Friday and in the game like on Forza Motorsport 2 there are levels (e.g. level 17 which im on) all the way up to Level 50, and each time you move up a level you unlock a car for you to have. I really want to know if anyone has a list of these cars and what level you unlock them at as I don't want to buy a car and then find out later you could have one unlocked free when you move up a level.



Hope it makes sense to you, Cheers =PForza Motorsport 3 Unlockable Help?
I found this complete achievement guide here, Courtesy of http://motorsportforza.com



Have a look as it may help you.

sprinter

international trucks