The success story of Audi's RS6 models has now lasted 20 years and four model series. With the very first model, the Audi sports department succeeded in transforming the rather staid A6 into a sports car suitable for families. In the meantime, the first model series have long since become classics and fetch collector's prices. This article tells the story of how the Audi RS6 came to be and gives tips on what to look out for when buying one.