http://www.rfactor.net/
http://en.wikipedia.org/wiki/RFactor

the future of race simulation, best car game ever

Its got everything full race series, great simulation, tuners and race car builders such as these guys

http://rfactor.net/rfmotors/h6/about.html
http://rfactor.net/rfmotors/kodi/index.html

Not a kids game, decent race simulation