Look, I don't want to engage or sidetrack this great thread over the Passon 855 vs Tremec or (whatever)
BUT
IF you don't want to cut your car and you want a 5 speed, the Passon is the answer.
Having said that, I didn't get my 855 because of not wanting to cut my car, I got it because it's a very strong transmission. I'm concerned about repairs, should it need them, and the cost and downtime, even availability of parts, but I've beat on it and will beat harder on it, and if it breaks I'll look at going to a radical 5 speed, along the lines of a Jericho or G-Force or...
The Passon is rated for 700 continuous Ft Lbs of torque, conservative rating, and it looks the part.