get the mach1 dude. get a manual version if possible, but an auto version is almost as good. use your computer and get it tuned.
the mach motor had the best non fr500 heads and intake. the auto version has a lower rpm limit, but not less hp. bolt on they run 12.8x quarter miles. add cams and ported heads and it goes even higher.
Bump, I was thinkin of doing the same with my 02' GT. Whats all involved in the swap? Mach crate motor and what else would be needed? Original poster has an 02' GT as well, so both of us have the T-3650, same tranny as the Mach (if he has manual).