Don't expect miracles in mileage from tuning or other parts. Your best bet for mileage is driving style and properly inflated tires. Using the cruise on the highway is a mistake. You can maintain the same speed with careful application of the throttle and keep the boost consistently 3-4psi below what you see with cruise. Boost requires fuel, its that simple. Over a long trip that can be the difference between 16mpg and 18mpg. The cruise control is a convenience feature. Our trucks have the first generation of cruise for Diesels. It wasn't possible before electronic controls, because all the OEM systems worked on vacuum, which Diesels don't make. So, it works, but it isn't super efficient and there are still some kinks.
All that being said, 12-14mpg around town and 16-18mpg highway is about all you can reasonably expect from these trucks. While towing those numbers are going to decrease.
'06 F250 4x4 - 5" Flo Pro exhaust, SB Filter intake, Accufab elbow, Edge Evolution (monitoring only), SCT w/ ID custom tune, FASS 195 pump, Gillette Diesel EGR cooler delete, Sinister Diesel coolant filter, ELC coolant, updated turbo drain tube/oil feed line/STC fitting/oil cooler, ARPs w/OEM HGs, Elite coolant lines, ITP RR fuel system, RCD 175/30 injectors, Powermax, BD CCV, FICM.com FICM w/ ID tune, Elite UP, BPD water pump - 13.069 @ 101.94
'02 WRX - Outback rear disc swap, EBC green pads, DBA pillar vane rotors, TXS UP/TBE/TMIC, Perrin LW crank pulley, PPG billet steel shift forks, ACT Streetlite flywheel & clutch, K&N filter, STi Group N motor/trans mounts, TiC/Kartboy rear diff mounts/subframe lock bolts/outrigger stiffeners, Kartboy SS & all shifter bushings, custom PDX tune for Cobb AP - went 14.1 on a terrible 60ft before most of these mods; shooting for 13.50s