I have a 2000 GT and my friend works for Ford as a mechanic and he took my car up on the lift and tried to re-flash the computer to recalibrate for my 3.73's and it was not possible. I don't know if Ford has changed that since the 00 Mustang, but he said they stopped being able to do it when the 99+ (New Edge) Stangs were built. I know he wouldn't lie to me his brother is one of my best friends. I think you'll have to get a speedcal or a chip or something. I had to get a calibrater from B&B electrics to get mine recalibrated. Like I said this was back in 2000, maybe it's different with Ford now.