What is the difference between the Audi A8 55 TFSI and A8 60 TFSI?

I am considering buying an Audi A8 but I am confused about the different model options. Can someone explain the difference between the A8 55 TFSI and A8 60 TFSI?

The main difference between the A8 55 TFSI and A8 60 TFSI is the engine size and power. The A8 55 TFSI has a 3.0-liter V6 engine with 335 horsepower, while the A8 60 TFSI has a 4.0-liter V8 engine with 453 horsepower.

Another difference is in the fuel efficiency. The A8 55 TFSI has a combined EPA rating of 23 mpg, while the A8 60 TFSI has a rating of 20 mpg. This may be a consideration for those looking for a more fuel-efficient option.

In terms of features, the A8 60 TFSI comes standard with Audi's Quattro all-wheel drive system, while the A8 55 TFSI offers it as an option. This can contribute to a smoother and more stable driving experience.