Hello All, I am new to the site, have lurked before and see that everyone likes to help out..And I need help. I have a 2001 Chev. Duramax 3500 dually with a MPRP 4inch exhaust and an AFE stage 2 air filter. What would be my next step in order to get some better mileage? I have been told to get a programmer but is there something else?