Although there are some similarities, these two are different in most aspects such as body structure, powertrain, fuel economy, market segment, and starting price. First of all, these two have similarly-sized dimensions, even though one is an SUV and the other a Sedan. Also, you get 73.6 more mpg with the 2016 Cayenne Hybrid, being a hybrid, than with the 2015 Model S. In addition, there is a $7,300 difference in the base MSRP. The Cayenne Hybrid has a higher starting price than the Model S. Among similarities are the market segment, ground shadow size, and maximum occupancy.