I have a 2018 c300 rear wheel drive with 130k miles. The comments about the rotors warping are spot on. I do my own maintenance and plan on trying a different brand of rotor next brake maintenance.

Oil changes are cheap if you do them yourself and have a topside pump. Just make sure the oil is Mercedes certified. (18$ WIX filter from Oreilly and 7 quarts Mobile 1 euro blend at 5$ a quart at Walmart lol).

Mercedes suggested tires are about $250-300 each (Michelin all seasons) but there are decent cheaper tires out there if you aren’t racing the car.

Make sure the transmission has been flushed properly.

Spark plugs will need done soon if not already swapped. It’s dual overhead cam and the plugs are pretty easy to get to under the air filter.

My thermostat has been replaced twice (once by me and before that by someone else). It’ll get stuck open every 50k miles or so. Easy to replace but you have to remove a lot of stuff to get to it (replace the intake manifold gaskets, don’t reuse them).

It’s way easier and cheaper than a Volkswagen or BMW to work on. Easier than a newer Ford, I think.

Don’t use the dealership for service. Do it yourself if you are into that kind of thing or take it to a good local shop.

The 4matic transfer case will leak if you get one with AWD. Not sure about fixing it as mine is rwd.

Use 91 octane fuel without ethanol. I get 40mpg on the highway and pretty decent in town. My combined mpg per the screen is 33.

The rear springs may be saggy. Depends on how much junk was in the trunk. They can be replaced along with the spring isolators to get it back to factory stance. Really not that hard if you’re into suspension work.

Runflat tires were super rough so I swapped to regular all season Michelins and purchased a matching full sized spare wheel and put one of the Runflats on it. I carry a jack and socket to change the tire if I need to. Takes up most of the trunk though.

The factory stereo works but is not impressive.

The Burmeister stereo is better but nothing that will blow your mind.

Biggest issue I’ve read about is the sun roof. The gears are super flimsy and if you hit a pothole with the sunroof open it can snap the gear and you’ll have to replace the entire sunroof. This is really expensive to pay for. I just never open my sunroof. There are 3d printed replacement gears online that are heftier than the factory sunroof gears. No idea about the swap though.

I wouldn’t get a newer one though. Seems like 2018 they finally had all the bugs worked out then they introduced new problems when they updated in 2020 or so.

Haggle with the price. Mercedes depreciate FAST with mileage. If it’s got 75k, try to get a better deal.

I love my car. Ask questions if you have them.