Although there are some similarities, these two are different in most aspects such as body structure, powertrain, starting price, fuel economy, market segment, horsepower, ground shadow size, and maximum occupancy. First of all, there is a significant difference between body structures and exterior dimensions. The 2015 BMW i3 is a Hatchback, while the 2016 Subaru Crosstrek Hybrid is an SUV. It is also slightly smaller. Also, a bigger engine usually means less mpg. But the 2015 i3 has a more powerful engine and it gets 89.5 more mpg than the 2016 Crosstrek Hybrid. In addition, there is a $16,005 difference in the base MSRP. The i3 has a higher starting price than the Crosstrek Hybrid. And then, there is a difference in the number of passengers; the Subaru Crosstrek Hybrid seats one more the BMW i3.