I am not saying the transmission needs to be rebuilt at all. Actually I have seen trannies with glazed clutches go more than 50,000 miles without any problems. If you apply more than 110hp in most cases the clutches will slip. That doesn't mean rebuild your tranny, unless you want more power.
You are correct there are a lot of hurt trannies out there. Some of our bigger tuners have hurt them, the Juice has hurt plent, the Hot juice, and I am sure you have. The fix is either back the power off, or buy a new one.
I have not failed to look at back pressure issues. Actually I know exact ratios for a given boost number, as well as a number for every cylinder. Yes they have a lot of backpressure, but its not as bad as you think until you make stupid power. We will have a fix for the backpressure issue in the near future.
Anytime someone mods a truck, especially if the go with higher hp, they are assuming somewhat of a risk. I really do not think that rpm will make any difference, unless it is abused. Lets face it, the only way to run much above 3700 rpm's would be to put the truck in a low gear and mat the pedal and not lift off. Do you really think people are going to be doing this for anything longer thana few seconds? I think there are much easier ways of breaking this motor than a few extra rpm's for a few seconds at a time. At that I am not sure there is enough fuel available to even hurt the motor with rpm's. Have you ever blown one up? I haven't.
Quad