Audi A7 Sportback (2017) is 285 mm (11.22 inch) longer, 127 mm (5.00 inch) higher and has 381 liters (13.45 ft3) bigger cargo space than BMW i8 (2015).
BMW i8 (2015) is 31 mm (1.22 inch) wider and 270 kg (595 lbs) lighter than Audi A7 Sportback (2017).