Peugeot 408 (2014) is 125 mm (4.92 inch) longer, 42 mm (1.65 inch) wider, 33 mm (1.30 inch) higher and has 107 liters (3.78 ft3) bigger cargo space than Subaru Impreza GT (2018).
Subaru Impreza GT (2018) is 200 kg (441 lbs) lighter than Peugeot 408 (2014).