What is the difference between the Audi A4 S line and S4 models?

I am interested in purchasing an Audi A4 but I am confused about the various models available. Can someone explain the differences between the S line and S4 models?

The main difference between the Audi A4 S line and S4 models is the engine. The S line model has a four-cylinder engine while the S4 has a V6 engine. This means that the S4 has more power and better performance.

The S line model is the sportier version of the Audi A4, with a more aggressive exterior design and some performance enhancements, while the S4 is a higher performance version of the A4 with a more powerful engine and upgraded suspension and brakes.

While both the Audi A4 S line and S4 models have similar exterior and interior features, the S4 has several additional features such as a sport differential, sport seats, and Audi Virtual Cockpit which make it a more luxurious and high-performing option.