A good number of the people I talk to who drive trucks are thinking about modifying their vehicles in some way to improve fuel mileage. The topic heats up every time gas and diesel take an upward hike or don't trend downwards after staying at what we consider to be the high side for awhile (and they're sure programming us for higher highs). I've made a few modifications to my truck, but additional changes haven't seemed practical when I compare the expense of doing it vs. the benefits the modifications will provide. But with a tank of gas costing close to $100 now, I'm leaning more towards making some changes. If your motivation is environmental, and expense isn't a factor, you're likely going to make any modifications you can to get better mileage. But if your intent is solely to save money, you should consider your driving habits and a few other factors before loading up the truck with fuel-saving accessories. Do the math.