BMW 8 Series (G15) (2018) is 514 mm (20.24 inch) longer, 113 mm (4.45 inch) wider and has 12 liters (0.42 ft3) bigger cargo space than Citroen C4 (2020).
Citroen C4 (2020) is 148 mm (5.83 inch) higher and 644 kg (1,420 lbs) lighter than BMW 8 Series (G15) (2018).