GMC Sierra 3500HD (2018) is 359 mm (14.13 inch) longer, 115 mm (4.53 inch) wider, 158 mm (6.22 inch) higher and has 831 liters (29.35 ft3) bigger cargo space than Mercedes X-Class (2017).
Mercedes X-Class (2017) is 557 kg (1,228 lbs) lighter than GMC Sierra 3500HD (2018).