Kia Optima (2016) is 199 mm (7.83 inch) longer, 510 kg (1,124 lbs) lighter and has 160 liters (5.65 ft3) bigger cargo space than Mercedes GLC-Class (2020).
Mercedes GLC-Class (2020) is 30 mm (1.18 inch) wider and 194 mm (7.64 inch) higher than Kia Optima (2016).