How so? The tuning on these trucks with the 05+ trucks is pretty aggressive compared to the 99-04 models. It's not a diesel and pulling 10k behind a 3V V10 is nothing. The last thing you want to do is start running tunes while dragging a trailer around. Nothing beats the factory tow haul mode setting.

V10's produce their peak power at 4250 -4500 rpm. Running anything past that is a waste. How would a tuner help In terms of power on a gasser?

On the pre 05 trucks it's a different story.