Why do some Audi 80 models have a boxy design while others have a more rounded design?

I've noticed that some Audi 80 models have a very angular, boxy design while others have a more rounded and aerodynamic look. What is the reason for this difference in design? Does it affect the performance or handling of the car?

The boxy design of some Audi 80 models was a deliberate choice by the designers to give the car a more classic and timeless look. It was also believed to provide better stability at higher speeds.

The rounded design of other Audi 80 models was a result of advancements in aerodynamic technology that allowed for better fuel efficiency and improved handling on the road.