Mercedes C-Class (Coupe) (2014) is 214 mm (8.43 inch) longer, 137 mm (5.39 inch) higher and has 169 liters (5.97 ft3) bigger cargo space than Porsche Cayman (2017).
Porsche Cayman (2017) is 30 mm (1.18 inch) wider and 200 kg (441 lbs) lighter than Mercedes C-Class (Coupe) (2014).