I'm looking at a couple trips within the next month that I'm taking my truck on. One while towing the other without. I have a 2007 Sierra 1500 ext cab with the 5.3L gas engine only performance mod is the K&N cold air induction kit. Is it worth buying a computer programmer for extra gas mileage empty and the extra power for towing? Anyone have a computer and can offer some input? Type of computer and increases (power/gas mileage) would be great!