What I personally have found is that my tuning will improve MPG with a ton less regen and almost no DEF use on the highway. This is with a 100hp over stock tune. Same results with our 30 and 60hp tunes. These tunes are a blast and get rid of the dead peddle feel and are very snappy. Spools faster than any model Dmax I have owned.
City driving and the MPG is about the same as stock with standard regens, mostly because it is so much fun to drive that the TPS is being abused.