I have an 07 2500 Z71 the truck gets 16 to 17 mpg with nothing more than a K&N filter added. The fuel consumption did improve after the first fuel filter change. Had two other dmax with Edege and had problems with both of them related to the programmer.
One upgrade that I did was a larger fuel tank 38gal made by transfer flo don't have to fill up every 3 1/2 days. The tank bolts under the truck in place of the small tank.