BMW 7 Series (2018) is 706 mm (27.80 inch) longer, 101 mm (3.98 inch) wider, 183 mm (7.20 inch) higher and has 364 liters (12.85 ft3) bigger cargo space than Porsche 718 Cayman (2017).
Porsche 718 Cayman (2017) is 419 kg (924 lbs) lighter than BMW 7 Series (2018).