BMW 8 Series (G15) (2018) is 12 mm (0.47 inch) longer, 45 mm (1.77 inch) wider and has 18 liters (0.64 ft3) bigger cargo space than Buick Regal (2015).
Buick Regal (2015) is 142 mm (5.59 inch) higher and 249 kg (549 lbs) lighter than BMW 8 Series (G15) (2018).