which tranny to go with

Well, 900 dollars later i have a broken t5 on my hands, with all the normal grinding second gear, 1st and 2nd gear pop outs not being able to slam second although still driveable its time to go bye bye. ive been researching the tremec 3550, tko 500 and 600, and the heavy duty t5 cant decide what to go with, nor can i find what it takes to convert any of these into a foxbody mustang. Need all of your opinions on this situation.







87 5.0 gt, world heads, tf stage 1 cam, msd 6a, parker polished alum intake, holley 750 dp, longtube headers, flows, 410 grs, broke ass t5