Chevrolet Impala (2016) is 258 mm (10.16 inch) longer, 31 mm (1.22 inch) higher and has 23 liters (0.81 ft3) bigger cargo space than Kia Optima (2015).
Kia Optima (2015) is 6 mm (0.24 inch) wider and 179 kg (395 lbs) lighter than Chevrolet Impala (2016).