There's a lot of argument today when it comes to picking the best RS car Audi ever produced. Old-school gearheads claim it's the RS2 Avant because it was produced with help from Porsche, while others claim the old RS models are no match for the modern variants. But people seem to forget that Audi also built performance versions of its full-size sedan, the A8. Granted, the S8 isn't a full-fledged RS model, but it packs a big punch and it combines it with luxury features in a unique way. The S8 badge goes back to the first-generation D2, a sedan that doesn't get the attention it deserves.