I ordered an 07.5 Chev HD2500 4wd Ext cab with the LMM. I plan on adding 285's before the truck leaves the dealer. I have read other posts indicating that the factory won't warranty the truck until the original tires are re-installed. I this still the case? Can the computer be programmed for the larger tires and if not will it hurt anything if I put them on anyway? Also, any recomendations on tire brand? Thanks