BMW 4 Series (2015) is 42 mm (1.65 inch) wider than Peugeot 508 SW (2016).
Peugeot 508 SW (2016) is 132 mm (5.20 inch) longer, 104 mm (4.09 inch) higher, 10 kg (22 lbs) lighter and has 85 liters (3.00 ft3) bigger cargo space than BMW 4 Series (2015).