BMW 8 Series (G14) (2018) is 40 mm (1.57 inch) wider than Buick Regal Sportback (2019).
Buick Regal Sportback (2019) is 57 mm (2.24 inch) longer, 116 mm (4.57 inch) higher, 223 kg (492 lbs) lighter and has 120 liters (4.24 ft3) bigger cargo space than BMW 8 Series (G14) (2018).