The S4 is, at its core, a modified A4. Thus it retains the four-door configuration and general dimensions of the smallest sedan Audi offers in the U.S.The S4 doesn't shout its presence (unless one chooses the Imola Yellow or Nogaro Blue pearl effect paint). Visual differences from the A4 models are limited to the wheels and tires, larger air intakes at the front of the car, and xenon headlamps with clear glass covers. Aluminum mirror housings are optional. S4 Avant gets aluminum roof rails. Next Page