CAI stands for Cold Air intake and a Gotts Mod is basically a cheap do-it-yourself intake for the truck. I'm sure you could more info on the Gotts Mod in the forums if you look around! Also there isn't much to raise the mpg as far as i know but horsepower can be raised slightly from a CAI or Exhaust or performance chip, you could find more about raising horsepower in the forums as well. Welcome and hope you like it here.