BMW 3 Series Gran Turismo (2018) is 45 mm (1.77 inch) higher, 81 kg (179 lbs) lighter and has 99 liters (3.50 ft3) bigger cargo space than Citroen C6 (2020).
Citroen C6 (2020) is 86 mm (3.39 inch) longer and 31 mm (1.22 inch) wider than BMW 3 Series Gran Turismo (2018).