Ford Flex (2016) is 211 mm (8.31 inch) wider than GMC Sierra 2500HD (2015).
GMC Sierra 2500HD (2015) is 958 mm (37.72 inch) longer, 262 mm (10.31 inch) higher, 439 kg (968 lbs) lighter and has 504 liters (17.80 ft3) bigger cargo space than Ford Flex (2016).