Although there are some similarities, these two are different in most aspects such as model year, body structure, fuel economy, market segment, and ground shadow size. First of all, body structures are completely different. One is a Sedan and the other a Hatchback. The 2016 Regal is also slightly larger than the 2013 Leaf. Also, you get 90.8 more mpg with the Regal than with the Leaf. Among similarities are the starting price and maximum occupancy.