What is the difference between Audi S models and RS models?

I am considering buying a high-performance Audi model, but I am confused about the different performance designations. Can someone explain the difference between S models and RS models?

Audi's S models are considered the entry-level performance models, with sportier design elements and improved handling and power. On the other hand, Audi's RS models are their highest-performing vehicles, with significant power and handling upgrades. Think of the S models as a toned-down version of the RS models.