Hello, i own a 2003 ford focus 2.3l duratec zx3 and im wondering if i should buy a sct tuner already programmed for my car or buy a unlocked sct tuner for any ford model. My only worry is that if i but a pre tuned sct will i be able to adjust the tunes because i am installing headers and exhaust and i dont want factory tune settings for aftermarket parts(hence why im buying a sct). I am wondering if i should instead buy and unlocked one. First off its 100 dollars cheaper ;D and second off i would be able to enter my own tunes rather then have sct give me tunes set for a stock focus. Please let me know As soon as possible even if im wrong cause i would like to purchase one as quick as possible thanks.