Here are some real numbers.
2010, 2500, Auto, 4wd, 373 gears, stock tires and wheels, 11,300 lb. 5th wheel, towing with cruise set at 62 mph. 1720 mile trip (Michigan to Florida)

Box stock mileage - 10.1 mpg down - 9.7 mpg back.

XRT PRO set at 60 hp. with deletes, delete pipe with stock downpipe - 11.1 mpg going down. I will post my return mileage in the spring.

The truck is slightly louder than stock with minimal drone while towing. The truck downshifts less often, how ever I quite often manually downshift to 5th before going up big hills on I75. Maximum transmission temperature observed was 168 degrees.

The driving fun factor alone after setting the XRT at 120 hp. for non towing is worth the investment.

I hope this information is helpfull - I know it is hard to find!