The game doesn't have many cars or tracks but they are good quality and there are heaps of free mods.
Get Content Manager and custom shaders patch, just look around for mods on the internet you will find websites with heaps of car and/or tracks. Great physics, just setup the wheel how you like it.
If you don't feel like spending as much money posted on the game now the are sales on 'big' holidays like Christmas and Easter on Steam.