Ford Flex (2015) is 221 mm (8.70 inch) wider and 576 kg (1,270 lbs) lighter than GMC Sierra 2500HD (2017).
GMC Sierra 2500HD (2017) is 575 mm (22.64 inch) longer, 250 mm (9.84 inch) higher and has 495 liters (17.48 ft3) bigger cargo space than Ford Flex (2015).