BMW 5 Series Gran Turismo (2018) is 551 mm (21.69 inch) longer, 66 mm (2.60 inch) wider, 173 mm (6.81 inch) higher and has 380 liters (13.42 ft3) bigger cargo space than Porsche 718 Cayman (2017).
Porsche 718 Cayman (2017) is 258 kg (569 lbs) lighter than BMW 5 Series Gran Turismo (2018).