Factors that differentiate the Audi S4 Avant from the Audi S4 are as follows. The Audi S4 is packing a massive V8 engine under the hood, whereas the Audi S4 Avant downsized the engine to a more modest V6 engine. While the Audi S4 is sporting a six stick gearbox, the Audi S4 Avant goes the extra mile with a seven stick gearbox onboard. However, both cars sport 18-inch alloy wheels and dual exhausts, and a 60:40 rear favoured four-wheel drive. Finally, there is a small difference in the price with the Audi S4, being sold at $56,000, while the more economical Audi S4 Avant is worth $59,000.