Kia Optima (2017) is 53 mm (2.09 inch) higher, 660 kg (1,455 lbs) lighter and has 20 liters (0.71 ft3) bigger cargo space than Mercedes CL-Class (2018).
Mercedes CL-Class (2018) is 240 mm (9.45 inch) longer and 12 mm (0.47 inch) wider than Kia Optima (2017).