Kia Optima (2015) is 431 mm (16.97 inch) longer, 56 mm (2.20 inch) wider and has 89 liters (3.14 ft3) bigger cargo space than Mercedes GLA-Class (2016).
Mercedes GLA-Class (2016) is 29 mm (1.14 inch) higher and 150 kg (331 lbs) lighter than Kia Optima (2015).