Just reading this thread and since I was tagged, I wanted to give you all a current (albeit belated) update. I still have the 2016 S550 4MATIC that I bought in Oct 2018 with 8,700 miles on it. At that time, I got the 2 year CPO extension to Dec 2023. As of today, the car has 146,141 miles on it. Although it has mostly been trouble free (I have done all routine maintenance and used OEM for everything), there were a few major repairs that WERE covered by the CPO extension (for which I had paid $4,000). It paid for a replacement CPU head unit, tie rod ends, and soft close doors for both front doors. I’m considering keeping the car past the 12/30/2023 CPO extension expiration (much to my wife’s chagrin) because with all the routine maintenance and 30k/year driving, I don’t see how I couldn’t easily get 500k miles or more out of the car. I’ve done the math and the numbers show that even some semi major repairs (if they happen) would be less expensive than buying a comparable car, which for me would be a 2 year old S580 4MATIC with less than 10k miles. We shall see. 😎