Question: The Audi RS4 quattro is the top tier and highest performing version of some specific generations of the Audi A4 range of automobiles, it slots distinctly above the Audi S4, the original Audi S4, built from 1991 until which year?
Sentence (from "Audi S4"): The Audi S4 is the high performance variant of Audi's compact executive car A4.
Relevant evidence: No