I've got 6.7 2500 auto, buddy has 6.7 3500 manual dually. After the warranty ran dry I deleted the DPF, egr, put on a programmer and cold air intake. I get 18.5 or so on the highway buddy has about the same mods and gets about the same mileage. Before mods I got 13. Pulling a load is 13 or less. I put all mods on after warranty and at the same time so I don't know what helped the most.
Close to the Same here on my 08' 6.7 4x4 mega cab dually.
6" suspension on 37's
Dpf deletes
Egr delete
H&s xrt pro
Tbe exhaust
Averaging 16-17hwy and 13-14 city
"the sun is shining somewhere in texas" -Jason Boland
