Mercedes GLA-Class (2017) is 32 mm (1.26 inch) longer, 34 mm (1.34 inch) wider, 318 mm (12.52 inch) higher and has 273 liters (9.64 ft3) bigger cargo space than Porsche Cayman (2016).
Porsche Cayman (2016) is 158 kg (348 lbs) lighter than Mercedes GLA-Class (2017).