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!
I have a combined weight of 26K and have never seen double digit mpg. We run about a 200 mile radius max but its up hill in every direction which is where the LBZ shines.