GMC Sierra 3500HD (2018) is 844 mm (33.23 inch) longer, 175 mm (6.89 inch) wider, 507 mm (19.96 inch) higher and has 1481 liters (52.30 ft3) bigger cargo space than Kia Optima (2019).
Kia Optima (2019) is 1155 kg (2,546 lbs) lighter than GMC Sierra 3500HD (2018).