Re: New F250 owner looking for help!
Only get an air intake if you want to chip the truck, otherwise just adding an air intake won't net you a mileage increase as it's a performance product that doesn't increase mileage on its own. Better breathing AND better exhaust can equal better mileage, however you'll feel compelled to romp on the go pedal more (it's OK though, we all do!).
Check your glove box for a sticker, it should have the axle ratio listed on it. If you have the 4.10 gears and don't tow anything and drive more highway miles than city miles a 3.55 swap may be in your interest and a reputable shop can do the swap for around $400-500. If you have 3.73 gears your best off sticking with those for general driving as a 3.55 won't make much of a difference in mileage and going any lower than that will increase transmission shifting, even on slightly inclined hills bringing mileage down, rather than up. If it's a manual transmission a lower rear gear may benefit but you'll lose towing capacity if that bothers you.
Also, a good tuner will give you multiple settings. Generally there's a towing setting, a performance setting and any other settings are a bonus. Just be cautious as the higher HP you go, the higher the EGT becomes.
For exhaust, check out Banks Power, they have several performance levels of tune available...but they're not the cheapest going. Once the truck gets some more miles on it the mileage should improve if ever so slightly. Keep the payload down and get rid of excess weight in the vehicle. Every 50lbs of weight lowers fuel economy by 1-2%
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!