Two Sedans with more similarities, such as the body structure, market segment, ground shadow size, height, and maximum occupancy, than differences, like the powertrain, starting price, fuel economy, market segment, and horsepower. First of all, a bigger engine usually means less mpg. But the 2017 Acura RLX Hybrid has a more powerful engine and it gets 9.8 more mpg than the 2017 Cadillac XTS. Also, there is a $14,355 difference in the base MSRP. The 2017 RLX Hybrid has a higher starting price than the 2017 XTS. Among similarities are the body structure, market segment, ground shadow size, height, and maximum occupancy.