BMW 4 Series (2016) is 8 mm (0.31 inch) wider and 115 kg (254 lbs) lighter than Buick Regal Sportback (2019).
Buick Regal Sportback (2019) is 202 mm (7.95 inch) longer, 72 mm (2.83 inch) higher and has 25 liters (0.88 ft3) bigger cargo space than BMW 4 Series (2016).