I just purchased a 2005HD Duramax 4x4 Crewcab/ Shortbed. Drove it from Texas where I purchased it to Colorado where I live and fell in love with the power, quietness and the ride. Bone stock for now, but want to improve power and mileage with a chip and exhaust what do you guys recommend for a chip and exhaust like manufactures and type. I will be pulling a 27.5 ft 5th wheel. Also does installing a chip and exhaust void the factory warranty? Thanks for any help.