BMW 5 Series Gran Turismo (2020) is 565 mm (22.24 inch) longer, 67 mm (2.64 inch) wider, 185 mm (7.28 inch) higher and has 368 liters (13.00 ft3) bigger cargo space than Porsche Cayman (2015).
Porsche Cayman (2015) is 340 kg (750 lbs) lighter than BMW 5 Series Gran Turismo (2020).