What are the most essential specifications to consider when comparing different model years of the Audi A1?

As a prospective Audi A1 buyer, I want to ensure that I am well-informed about the differences between various model years so that I can make a confident purchase decision. What are the key factors to consider when comparing different model years?

The engine size and fuel efficiency should be a top priority when comparing different model years of the Audi A1. The newer the model, the more likely it is to have a more efficient and powerful engine, resulting in a smoother and more enjoyable driving experience.