This is a big truck... but I do shoot for EPA+ economy most of the time. Lately, I've become even more interested in getting more economy from the truck, so my average will start climbing a little. After a recent build-up on the engine, I'm getting better average economy.
Stock ECM program.
Stock-sized tires, Michelin, the best rolling resistance available for the size/load. Improved air intake systems to reduce turbulence and increase air flow efficiency. 5" turbo-back exhaust. Synthetic fluids in trans/tcase/axles. Gauges for monitoring boost/pyro/fuel rail pressure/lift pump pressure. Stubby/stiff rear mud flaps (flaps required by law, cannot be deleted) that stay out of the way of most of the air flow. UltraGauge / Tonneau
/ Belly Pan / Wheel covers for the outer rear wheels or possibly (and possibly?) fender skirts / front mud flap delete (when running boards are finally installed, won't need them) / front grill modifications / air dam