What is the difference between the Audi A3 and A4 engines?

I am considering purchasing an Audi A3 and I'm not sure if the engine specs are worth the price difference compared to the A4. What are the major differences between these two engines?

As an Audi dealership mechanic, I can assure you that the engines in the A3 and A4 are quite different. The A3 has a smaller, more fuel-efficient engine while the A4 has a more powerful engine with better performance. It ultimately depends on your driving needs and preferences.