What is the difference between a 45 TDI and 50 TDI engine in the Audi A6?

I am in the market for a new Audi A6 and I am confused about the different engine options. Can someone explain the difference between the 45 TDI and 50 TDI engines?

The main difference between the 45 TDI and 50 TDI engines is the power output. The 45 TDI has 231 horsepower and 500 Nm of torque, while the 50 TDI has 286 horsepower and 620 Nm of torque.

In terms of fuel efficiency, the 45 TDI and 50 TDI engines have a similar fuel consumption, with the 45 TDI being slightly better. However, the 50 TDI offers a smoother and more powerful driving experience.