The HD Silverado and its twin the GMC Sierra HD are designed for heavy towing and hauling. The 6.0-liter V8 and 6.6-liter turbodiesel are both mated to a six-speed automatic. The latter works well, and employs a heavy-duty Allison-made transmission. There is also a natural-gas version of the 6.0-liter V8. The LTZ trim has a luxurious cabin. If you don't plan to go off-road, the Z71 suspension is superfluous -- it tends to compromise ride comfort. The HD pickups are the better choice for commercial snow-plowing duties. Available safety features include forward-collision alert, lane-departure warning, and front and rear park assist. Apple CarPlay and Android Auto are compatible with the infotainment system.