McLaren GT (2020) is 265 mm (10.43 inch) longer, 299 mm (11.77 inch) wider, 54 kg (119 lbs) lighter and has 15 liters (0.53 ft3) bigger cargo space than Mercedes B-Class (2020).
Mercedes B-Class (2020) is 348 mm (13.70 inch) higher than McLaren GT (2020).