All I can say is HOLY CRAP! Coming from a 2000 6.0 vortex this set up is awsome! The truck doesn't even flinch! 70 and sunny about 70 miles from home and 12.2 MPG--NICE! I am grinning!
Congrats and welcome to the LBZ world. Mine gets between 9-13mpg depending on wind, terrain and speed. I actually look forward to towing with mine to see if there are any obstacles that I can't climb. So far none.