BMW 5 Series Touring (2018) is 628 mm (24.72 inch) longer, 95 mm (3.74 inch) wider, 272 mm (10.71 inch) higher and has 408 liters (14.41 ft3) bigger cargo space than Porsche Cayman (2016).
Porsche Cayman (2016) is 496 kg (1,093 lbs) lighter than BMW 5 Series Touring (2018).