What does the Audi A7's quattro system do and how does it improve driving performance?

I'm considering buying an Audi A7 and have heard about the quattro system. Can you explain what it does and how it impacts the driving experience?

The quattro system in an Audi A7 is a permanent all-wheel drive system that helps improve traction, handling and overall driving performance. It distributes power between the front and rear wheels to optimize grip and also works in conjunction with the car's stability control system.

Having driven an Audi A7 with the quattro system, I can attest to its ability to improve handling and stability during inclement weather conditions. The car feels planted and in control, even on wet or slippery roads.