I have a question for the masses. I have an 05 super cab Lariat with a factory installed 3:55 rear end. I want to change it out to something like a 3:05 for better economy and because I don't do any towing and spend lots of time on the highway. What all am I looking at and do you all think the gain will be worth the cost. I keep hearing that these trucks can get close to 20 mpg, I need that. I'm only getting a little over 16 right now.

Thanks