What are the differences between the first generation and second generation Audi A2 models?

I am considering buying an Audi A2 and I have come across both first and second generation models. Can someone explain the differences between the two?

The first generation Audi A2 models were produced between 1999 and 2005, while the second generation models were produced between 2005 and 2009. The main difference between the two is the design, as the second generation features a more modern and sporty look compared to the first generation. Additionally, the second generation also has improved fuel efficiency and more advanced technology features.