Audi S8 (2015) is 343 mm (13.50 inch) longer and 23 mm (0.91 inch) wider than Mercedes M-Class (2015).
Mercedes M-Class (2015) is 320 mm (12.60 inch) higher, 844 kg (1,861 lbs) lighter and has 185 liters (6.53 ft3) bigger cargo space than Audi S8 (2015).