This guide includes information necessary for buyers of Audi S4 biturbo.Audi S4 biturbo was first released in Europe in 1998, with North America and Canada being introduced to the model in 2000, so there are actually two different models available in Europe. The external differences can be seen quite quickly, with early vehicles featuring square side-repeaters, thin body-mouldings, flush mounted door handles, and Xenon headlamps with separate indicators. It takes quite an eye to see, but you may also note that the door-mirrors on earlier cars are not quite as “angular” as those of its successor. You’ll also need to know when browsing through local classifieds and dealer pages that an S4 listed as circa 1994 is not a misprint, and while it is a fabulous car, you do not want to waste valuable time looking at it! The early S4’s (or urS4’s as they are sometimes referred to) are based on the last model Audi 100 cars, and feature a 20-valve 5-cylinder turbocharged engine as found in the Audi S2. This guide gives information for buyers excluding information on modern vehicle systems like gps vehicle tracking. Free download Buyers guide Audi S4 Biturbo.