Just out of curiosity, did you order the GT500 sight unseen? Unless I'm completely oblivious to the recent Ford stuff, I haven't seen any release of the new mustangs design??
But more on topic, I would say like a 4 or 5 for my car...I just get the feeling that its too slow to beat on sometimes so I just drive it and have a little fun here and there. Wish I had the money for performance upgrades
The 2014 GT500 is the same as the current 2013.