BMW 2 Series (2016) is 54 mm (2.13 inch) longer, 125 mm (4.92 inch) higher and has 228 liters (8.05 ft3) bigger cargo space than Porsche Cayman (2014).
Porsche Cayman (2014) is 26 mm (1.02 inch) wider and 10 kg (22 lbs) lighter than BMW 2 Series (2016).