McLaren GT (2020) is 306 mm (12.05 inch) longer, 295 mm (11.61 inch) wider and has 258 liters (9.11 ft3) bigger cargo space than Porsche Cayman (2015).
Porsche Cayman (2015) is 79 mm (3.11 inch) higher and 166 kg (366 lbs) lighter than McLaren GT (2020).