GMC Sierra 2500HD (2020) is 1127 mm (44.37 inch) longer, 218 mm (8.58 inch) wider, 554 mm (21.81 inch) higher and has 1217 liters (42.98 ft3) bigger cargo space than Kia Optima (2017).
Kia Optima (2017) is 1209 kg (2,665 lbs) lighter than GMC Sierra 2500HD (2020).
