What is the difference between Audi A8 55 TFSI and Audi A8 50 TDI?

I am in the market for a luxury sedan and am looking at the Audi A8. However, I am confused about the different models available, particularly the difference between the A8 55 TFSI and A8 50 TDI. Can someone explain the technical differences between these models?

The main difference between the A8 55 TFSI and A8 50 TDI is the engine type. The 55 TFSI has a gasoline engine while the 50 TDI has a diesel engine. Both engines have their own benefits and downsides, so it really depends on your driving habits and preferences.