Right now I have 5" from cat back with an aftermarket muffler. If I were to drop the cat and muffler how much cooler will it run? I hate to do it because it's gonna be loud but need some reprieve from the heat.

 

How hot is it running now? And where is your probe?

Youll get a little bit of a drop if you go 5" turbo back, on my '07 I probably dropped about 75-100* cruising, and definantly dropped more laying into it.

 

On tow tune I can get to 1200 but not much past, on performance it'll peg the gauge and that's all unloaded without full pedal. About to yank 10k cross country and don't want any issues while towing. My probe is about 2" above the the turbo flange on the back half.

 

Have you towed with it on the tow setting yet?
1200 isnt too bad, I wouldnt tow 10k with it on performance thats for sure

Youll still have some higher EGTs with that diablo though, just how some of the programmers/boxes are, some get you the power with higher egts...
The Edge Juice/attitude I had on my old '05 ran hotter than the Smarty ever did, still made great power and was a nice box for the money, but it was still about 100-150* hotter when you were in the skinny pedal than the smarty...

 

Have not towed a loaded trailer but did pull my empty 22 ft car hauler on performance tune. I will start in the tow tune and if it gets too hot just drop it to stock. Not too much drastic elevation change on the highways between ga and sw az.