The S8 plus is an absolute beast which can go toe to toe with rivals from AMG. With 605 hp, the S8 sits right between the 577 hp S63 and the 621 hp S65, which is actually slower and a bit pointless. We absolutely love the S8 plus, and definitely think that is deserves to be the top-dog of the A8 range with a $114,900 price tag. However, the S8 plus is not the most expensive A8 that you can buy. That honor belongs to the A8 L W12 at $137,900. Not only did we forget that Audi still offered a W12 A8, we certainly didn't realize that it was still the most expensive model in the entire lineup that doesn't start with the letter R. So why does the W12 deserve to be over $20,000 more expensive than the amazing S8 plus?