The Audi stand at the Frankfurt Motor Show is amazing in its own right. However, the vehicles on display aren’t as sexy as those shown by Mercedes-Benz. Case in point, while the AMG fellows dropped a new C63 Coupe, quattro only had the S4.

Compared to the S models Audi has built on the MQB platform (S3 and TTS), the S4 sedan is a bit underwhelming. While the average C400 or C450 AMG models use twin-turbo 3-liter engines, Audi chose t…