Hi there Cal. You live in one of my favorite towns as we raced at Red Cedar Speedway for a LONG long time!
Certainly the gearing is different between the two boxes.
I have seen only a few cars that could make "good use" of the .68 5th gear - my own included. The .82 5th gear makes much more sense and is available for the same price.
The really nice part about the 3.27 first gear in some of the Tremec's is that you can gear the differential more for higher speeds while generating less heat and HP loss through friction/heat. It's all about proper design and implementation of all the components in the driveline.
According to my notes from my conversations with Julio, the basis of the TR3550 (and the TKO derivatives) is the main shaft, countershaft spacing, design and implementation of the sliders, synchronizers (blockers) and finally the design / pitch of the gears themselves. They were in the process of creating the TKO at the time of our discussion. At that time they were concentrating their efforts on the heat treating of the gears and beefing up the diameter of the output / main shaft to reduce flex and torsional stress.
The material on the inside of the blocker rings you are talking about is probably the same carbon fiber traction ring that BW had pioneered in the World Class T5.
In my own car, the transmission (TR3550) shifts smoothly and very precisely. The only issue I have had is a slight grind on up-shift to 3rd when the transmission is really hot (20+ laps). This will probably go away when I change the lube before the next race. There is absolutely no grinding on down-shifting - I could not ask for a more precise shifting transmission and my customers tend to agree.