There are lots of businesses and individuals out there doing whatever they can special vehicle keep away from paying the HVUT. Many will lie along the weight of their total vehicle or even register a vehicle as exempt when this is anything but exempt.
Will make use of the tonneau to only haul items occasionally or do you'd like to the idea often? Would you like be hauling expensive items such as tools, sporting gear, travel luggage, consequently on.? If so, then be sure the tonneau cover can be locked and tightly sealed to protect items out from the weather conditions. If you use your GMC truck for work, the retractable tonneau by Pace Edwards is a large quality Boom Truck bed cover in which save serious cash in the future run. It may possibly even be counted for a business deduction for tax purposes!
Most side mount toolboxes are made in aluminum, metal or wood. Some are formulated of hard plastic also, with door opening similar to small pantry.