Two Sedans with some similarities, but otherwise different in most aspects such as the model year, powertrain, horsepower, fuel economy, height, and maximum occupancy. First of all, the 2016 S4 has bigger and thirstier engine; the 2013 E-Class Sedan Diesel gets 4.5 more mpg. Also, the S4 is slightly shorter than the E-Class Sedan Diesel. In addition, there is a difference in the number of passengers; the Mercedes-Benz E-Class Sedan Diesel seats two more the Audi S4. Among similarities are the body structure, market segment, starting price, and ground shadow size.