I wouldn't waste my money. I know my tuner, Jason Hackler has explained exactly why it's a waste, but this guy summed it up pretty well too. This was from a discussion about it on one of the Facebook groups:
"Do you understand what that module does? All it does is remap the throttle input so instead of 10% throttle input translating into 10% throttle desired at the ecu it will be like 30% it just increases the rate of throttle opening.
YOU CAN DO THIS FOR FREE by pushing on the throttle harder lol.
Increases mileage? are you kidding me, it hasn't done anything, why would mileage be any different maybe worse because you will be accelerating harder all the time. At cruise it wont do a damn thing."
And I would not use it with your tuning, if you got a tune. You won't need it at that point, there is no dead pedal left after you tune the truck.