Hey guys new to the site. I guess a few questions. I'm thinking about buying a silverado 2500 hd with the 6.0L motor for better towing. currently have an 04 avalanche with the 5.3L. What can i expect real world fuel mileage wise out of the 6.0L, and if i get a gas programmer right away which i would, what kind of fuel mileage could i expect then? I get 14/18 average with the Avalanche and hope with adding the programmer to the 6.0L I wouldn't be far off of that for daily mixed driving. Thanks for the help.