You can always do more...subtle mods, and still make it look stock. Port the head, gut the intake, port out the exhaust manifold, and keep stock turbo and intercooler. And at least upgrade to a roller cam, even if it is the stock ranger roller cam (nobody will be able to tell unless they open the motor) and maybe an adjustable FPR and Gillis valve. Add a tune and you could still have some fun with it, and alot of that work can be done yourself to the existing parts. Maybe I'm just a diehard modder, but I just can't bring myself to not modify a mustang. Just can't do it. But you can definately make some extra power and keep it looking like a stock motor. Hell, even if you just throw a little extra boost at it.