Well, your going to get a lot of opinions on that question. T-5's were built for everything from little 4 bangers up to the world class (WC), which I think is rated to 300lb/ft of torque. Even a mild 302 will break the little ones, the WC will make it if not abused. The WC T-5 in my 320 yblock, with over 300lb/ft will turn the 235/60 t/a, with posi. But I don't do it often.
Next, T-5's came with a variety of gear ratios, most importantly something around 3.27 to 2.95 in low (maybe more), an at least a couple different O/D. If you don't watch this, and your rear gear/tire size, you get to change the rear gears to make it drive right. Ask me how I know.
Next step up is the TKO series, I think. The TREMEC site will give you info on all the new ones.
I've got the T-5 in one car, a TKO500 in another, both 2.95 low and .8 O/D. Love them both. The TKO model has 3 places to mount the shifter, which can be of help.
I did both these 7-10 years ago, so don't trust my memory, go check it out.