I'm running a Richmond Super T10. It was purchased new and works perfectly, but if I had my choice I'd rather have a Muncie M22 just for the sound they generate. I really didn’t want a 2.20 low gear however with the close ratio gear spread. I wanted wide gear separation since drag racing isn’t much of a priority for my truck.
Mine is the 2nd selection listed with the 2.64 low good for 325 lbs ft of torque. The 2.43 is good for 375 lbs. I haven’t been able to find a legitimate torque rating for the Muncie to compare their strength.
Also FYI - my ex-wife had an 86 Trans Am with a T5 and the factory roller cam V8. I think it might have been a 305, I was getting a divorce at the time so I don't remember much about it other than the transmission failed before they could deliver the car, and it broke two more times within warranty. Of course she let 2 teenage sons beat the crap out of it, but it wasn't much of an engine - so I'm thinking that particular T5 must not have been much of a transmission either.