Mercedes GLA-Class (2018) is 272 mm (10.71 inch) longer, 54 mm (2.13 inch) wider, 59 mm (2.32 inch) higher and has 35 liters (1.24 ft3) bigger cargo space than Seat Arona (2017).
Seat Arona (2017) is 476 kg (1,049 lbs) lighter than Mercedes GLA-Class (2018).