Buick Regal (2016) is 1 mm (0.04 inch) wider than Opel Insignia Sports Tourer (2015).
Opel Insignia Sports Tourer (2015) is 82 mm (3.23 inch) longer, 30 mm (1.18 inch) higher, 75 kg (165 lbs) lighter and has 158 liters (5.58 ft3) bigger cargo space than Buick Regal (2016).