I have a 2003 Dodge 3500 CC Dually that is my everyday work truck. It has about 135K miles on it now, still running strong. I average around 16-18mpg right now empty. I'm mostly doing highway driving to different job sites going 75 or so. If I only go 65 I can get 21-22mpg but it takes forever to get there. When I tow I'm usually around 10K-18k lbs. I've been thinking of a hypertech programmer to help with mpg and maybe an exhaust system. A little more HP for towing would be nice as well. As this is a work truck I don't want to spend tons of money. Any thoughts would be great.