BMW 5 Series (2018) is 43 mm (1.69 inch) longer, 5 mm (0.20 inch) wider, 44 mm (1.73 inch) higher and has 99 liters (3.50 ft3) bigger cargo space than Buick Regal Sportback (2019).
Buick Regal Sportback (2019) is 15 kg (33 lbs) lighter than BMW 5 Series (2018).