How to get better gas mileage

You couldn't be less accurate. I said there are very few consistently cost effective ways to increase mpg, none of which even approach the effectiveness of conservative driving. No item you listed short of a regear (and even that is questionable) will increase your mileage more than simply driving more intelligently.

Go ahead and run the numbers on...say... exhaust, air filter, re-gearing, and adding an electric fan. Add up the purchase price and installation costs. Assume a REALISTIC increase in mileage and see how long it takes to make your money back.

If you even begin to consider that adding a supercharger or a turbo is a potentially cost effective way to increase your mileage I think any further discussion would be a huge waste of both our time.

 

The proper way to increase your trucks fuel economy is to learn how to drive efficiently. It's 100% free to drive differently, and you can see significant increases in MPG.