BMW i8 (2015) is 82 mm (3.23 inch) wider and 266 kg (586 lbs) lighter than Kia Optima Sportswagon (2018).
Kia Optima Sportswagon (2018) is 166 mm (6.54 inch) longer, 177 mm (6.97 inch) higher and has 286 liters (10.10 ft3) bigger cargo space than BMW i8 (2015).