Any year MTX-2 or 3 will bolt up to the GT. The 2's are four speed, and usually higher geared. The 3's are five speeds, and usually lower geared. The GT tranny has the lowest gearing for performance, followed by the LX 5 speed. A Tempo 5 speed will be just fine too, as I'm currently driving with one...I like the inspection hole for timing, too (Tempo flywheel and tranny shim required).
Here's a link for info on pretty much all models of MTX...very accurate and handy.