What are the key differences between the Audi A7 and the Audi S7?

As a potential Audi A7 buyer, I'm curious about the differences between the A7 and the S7 models. Are the performance, features, and costs significantly different?

The key difference between the Audi A7 and S7 is the engine. The A7 is equipped with a 2.0-liter turbocharged engine while the S7 has a more powerful 4.0-liter twin-turbo V8 engine.

In terms of performance, the S7 boasts a faster 0-60 mph time of 4.3 seconds compared to the A7's 6.2 seconds. However, the A7 has a slightly higher fuel efficiency with an EPA estimated 22 mpg city and 29 mpg highway compared to the S7's 18 mpg city and 28 mpg highway.

When it comes to features, both the A7 and S7 share many similar ones such as leather seats, MMI infotainment system, and sunroof. However, the S7 offers upgrades such as an upgraded Bang & Olufsen sound system and a heads-up display.