Two Sedans with some similarities, but otherwise different in most aspects such as the model year, horsepower, fuel economy, market segment, and ground shadow size. First of all, the 2016 IS 300 has a more powerful engine than the 2013 Fusion Energi, and it gets 17 fewer miles on a gallon of fuel. Also, the body structure of Fusion Energi is slightly larger than that of the IS 300. Among similarities are the body structure, starting price, height, and maximum occupancy.