I had a '12 that was put on a diet w/ the mm, g3arhead tune, 5" exhaust, egr, NL intake etc.
It ran like a raped ape and got 18mpg doing it at 80mph. Towed a big toyhauler like a champ too.
Great. Only thing I didn't like is that it was real hard on tires :D Maybe a left foot problem.
Wifey...