Someone just asked this question, http://www.fuelly.com/car/mercedes-benz/c450_amg

As for reliability, make sure you get extended warranty...

 

 

I have a 2016 C450 and in the almsot 3 years I've had it, I've put about 34,000 miles on it and it has been quite reliable. It's been in the shop once for a new rim/tire, thanks to a very stealthy New England pothole ( the wheel & tire coverage paid for itself on that one!), so ZERO problems from a reliability standpoint, here ( although that may not be a uniform experience across this forum).

As far as fuel economy, I drive aggressively on most days ( excepting when work beats me down a little too much) and I find I can get up to 27-28 mpg when comfort cruising the highway and around 20 in city/town driving/stop&go/traffic siutations. I average about 21 mpg overall. Hope this helps

 

I drive it like I stole it. I get high teens in heavy congested city traffic and 25-27mpg on the open hwy running between 75-85 mph. If you go easy, your mileage will be significantly better than mine.

 

Kind of unrelated:

People were right about the transmission updates. I used to get, from my recollection, 10.4-12.4 L/100km city and 8.4-8.9 L/100km highway before the tranny update.

Now I get about 12.4/10.1. I think what the update essential does is increase the throttle response and dump more fuel during low depression so it doesn't trick the transmission into hesitating as much. But honestly, my 2018 that I got 4 months ago felt pretty much identical, not much "smoother" as others would have described. I think I would trade off any smoothness "increase" back for my original mileage haha. Still not bad for a supposed sports car. Definitely better than a V8 but if you give it the beans, expect it to shoot up to 19+ L/100km.

 

 

My experience exactly (minus the pothole & new rim/tire). I'm even STILL on the original run-flat tires. Will be replacing those before Old Man Winter rolls in, though....