1st off forget about Gran Turismo and Forza! Games don't get more realistic than this.
The level of tweaking and modification that can be done in this game it's beyond anything on the market, you can setup suspension,wheels,tire pressure,downforce,fuel induction transmission and many other things to a professional level...sometimes it gives you the impression that you have to be a mechanic to figure out what you're doing and i'm saying this in a good way.
Tire wear out,they get hot,they get cold,they get dirty they even have damage!
Anyway if you-re a petrol-head like me and love driving and racing you should check this out because the A.I. Is one of the best i've ever seen and the online scene it's crazy! World championships records no cheaters and all that. And did i mention that it's made by a team of three i repeat THREE persons?
A game for professionals,made by professionals.