BMW X6 (2015) is 9 mm (0.35 inch) longer, 127 mm (5.00 inch) wider, 247 mm (9.72 inch) higher and has 110 liters (3.88 ft3) bigger cargo space than Buick Regal Sportback (2018).
Buick Regal Sportback (2018) is 358 kg (789 lbs) lighter than BMW X6 (2015).