Introduced in the 2000 model year, the Audi S4 is a high-performance version of Audis most popular model, the A4 sedan (which was first unveiled in 1996). Audi defines the S4 as a vehicle concept that perfectly combines superior performance with masterfully understated appearance, without sacrificing everyday practicality. Take out the flowery adverbs and adjectives, and thats a fairly accurate definition of this very fast, very attractive five passenger performance sedan