My 05 6.0L gets 14mpg highway DRY running the BullyDog GT (on Tow), 35" mud country's, and a catback exhaust no muffler. Rear end is 3.73. I know...its a truck, but most 6.0L guys i talk to average 17-21 mpg (chip or no chip) as so they say. Any ideas on how i can bring my mpg up. Remove cat? Air intake?