I think Dave hit the nail on the head. The HI-rpm gear banging is killing the synchros. Really has nothing to do with what the tranny is rated at strength wise. He isnt breaking gears, or main-shafts.

Have you lock-tites the bump-stops? All the hi rpms may have vibrated loose the bump stops letting the shiftfork overextend. I know little Dave ( 99GT) was having problems bending shiftforks but he hada T-45 setup.

What kinda power are you putting through that lil t-5 anyway?

I remember seeing your car at sunshine running my buddys lighting door2door... I was driving the POS merkur that kept breaking