Audi S6 (2015) is 76 mm (2.99 inch) longer and 14 mm (0.55 inch) wider than Kia Optima Sportswagon (2018).
Kia Optima Sportswagon (2018) is 30 mm (1.18 inch) higher, 69 kg (152 lbs) lighter and has 41 liters (1.45 ft3) bigger cargo space than Audi S6 (2015).
