2010 Silverado 1500 Z71 4X4 5.3 w/six speed auto and 3.73 rear . Moving cross country in a couple months, have not used any programmers to reset for bigger tires. Plan on towing wife's Camaro. Will a program help with gas mileage or/and adjust shift points so it will be better on my Silvy towing and moving from sea level to 6000 feet? Will it be a permanent change, make a difference when not towing? Thanks for any input y'all may be able to provide.