BMW 3 Series Gran Turismo (2018) is 30 mm (1.18 inch) higher, 125 kg (276 lbs) lighter and has 6 liters (0.21 ft3) bigger cargo space than BMW 7 Series (2018).
BMW 7 Series (2018) is 274 mm (10.79 inch) longer and 74 mm (2.91 inch) wider than BMW 3 Series Gran Turismo (2018).