Too bad it won't work on a 2003 gt... (drive by wire)
Why wouldn't it work?
And my 2003 GT is with a throttle cable, so I doubt yours has a drive by wire system.
MIne is drive by wire and no the power FC will not work.. I have called them personnaly and they said they are working on one but, it will take some time. One way to see if your car is drive by wire is look at your gas pedal. at the top if it has a black cylinder and just has one wire hooked to it then it is drive by wire. You might want to check yours...