I got very lucky with my car because i bought the car from a non mb dealer but the car was previously a certified vehicle (i'm the 3rd owner) and i was able to contact another mb dealer to purchase the extended warranty, which i found from this forum (2 yrs extra/unlimited miles for like 2500 or something like that). and even when i bought the car from a non mb dealer, the dealer had no issues and didn't give me any issues taking care of any warranty issues, which was both front axles, and some update to get the parking brake set on automatically when the vehicle is put in park (2015 models didn't have that but 16s and up did), which they told me my certified extended warranty didn't cover so they said i had to pay for it so i agreed on paying for the update but when i got there to pick up the car, they somehow got it taken care of under the warranty. Other than those, the car has been bullet proof so i wouldn't really be afraid to buy it non cpo but c300 is a different story since some people had the wrist pin issues, which i believe the 16s didn't have any issues of. The only thing that broke on my car outside of factory warranty was the pano roof, which isn't under the cpo warranty. It wasn't closing past 80mph and according to the dealership, the track was broken or something and the cost to replace the track and the motor was over 3k so i ended up passing on it since i could just slow down and close it. I bought the car in april of 2017 with only 22k miles on it and as of today, the car has 80k miles on the car and the car is still running pretty strong. I do abuse my car from time to time and as you see, i've racked up a lot of miles on the car but she's been running pretty well. I do take good care of the car so if you do the same, i don't see why the car won't be reliable in general. I do mobil 1 0w-40 full synthetic oil change with the factory filter every 6-7k miles instead of 10k mb recommends and I got the transmission and the front and back diff oil replaced around 55k miles along with new spark plugs.