It's easy to increase the power with a tuner, but if you want power you are more than likely not going to increase your mileage. I run the setup in my signature and normal unloaded highway driving yields around 18 mpg. Loaded with the toys I get around 13 mpg. Use the search forum and you will find more than enough info on the different mods you can do to your truck as long as you have the funds to support it. Another thing to keep in mind with adding power is that you need to consider upgrading your transmission to handle the power. Good luck!
Hop