BMW 8 Series (G14) (2018) is 345 mm (13.58 inch) longer, 115 mm (4.53 inch) wider and has 50 liters (1.77 ft3) bigger cargo space than Opel Ampera (2014).
Opel Ampera (2014) is 100 mm (3.94 inch) higher and 266 kg (586 lbs) lighter than BMW 8 Series (G14) (2018).