The Audi S4 is the high performance version of the standard A4. This model commands a 10K price premium over the standard A4 but is worth every penny. The S4 offers superb ride and handling and is generally unflappable despite being a bit heavy. The 340hp engine provides an exhilarating driving experience enhanced by the feedback from the rumbling V8. There are few visual differences between this car and the stock A4, but many rewards for the driving enthusiast.