I play iRacing, Assetto Corsa, and Richard Burns Rally with a Logitech G27. I used to play Forza and Gran Turismo and they honestly don't even come close to the physics modeling and force feedback that PC sims offer. They may as well be arcade racers in comparison.
If you want to see how a GT-86 feels in a real racing sim, Assetto Corsa is getting both a street and a track version in a future patch:
http://www.assettocorsa.net/assetto-...g-rsr-nurburg/