What is the difference between Audi's TFSI and TDI engines?

I've heard about Audi's TFSI and TDI engines, but I'm not sure what the difference is. Can someone explain it to me?

The TFSI engine is a petrol-based engine while the TDI engine is a diesel-based engine.

TFSI engines use a turbocharger to increase power and efficiency, while TDI engines use a turbocharger and direct injection technology for the same purposes.

If you're looking for speed and performance, go for the TFSI engine. If you're more concerned about fuel efficiency and low-end torque, the TDI engine is the way to go.