What are the key differences between the Audi A1 and A4?

I've been looking at both models and can't seem to decide which one would be a better fit for me. I'm looking for a compact yet powerful car, but also want something with good gas mileage and technology features.

The main difference between the Audi A1 and A4 lies in their size and engine power. The A1 is a smaller and more compact car, perfect for city driving or those who prefer a smaller vehicle. On the other hand, the A4 is bigger and more powerful, making it a great option for long distance driving and a smoother driving experience overall.