2012 Mercedes-Benz C-Class C250 Sport 4dr Sedan (1.8L 4cyl Turbo 7A)
Mercedes-Benz just bought back my 2012 C250 because of untraceable electrical issues. I do accept that this was just luck of the draw, a fluke, the random lemon, etc., and don't believe that my car was indicative of the model. I would have random electrical issues like non-functioning buttons, seat controls and warning lights, that would magically correct themselves the next morning. Dealer and even MB regional tried to identify the problem, but failed, ultimately just buying back my car. That said, the C250 was a blast to drive, smoother, more powerful and efficient than the C300 it replaced. Still highly recommended. I replaced my car with a certified 2011 C300.
The smooth turbo 4. This engine is actually smoother and quieter in operation than the V6 it replaced. The updated electronics and entertainment package is also a delight, though perhaps it was the reason my car had so many electrical problems. My guess is that there was just some bad transistor in a memory chip somewhere (these cars are highly computerized) that caused all of the issues. The balance of ride and handling, as on previous W204 C class cars, is also about perfect for people who enjoy driving, but spend A LOT of time on the road. The 3 series is sportier, but nowhere near as comfortable.
Improve responsiveness at low RPM or when the turbo is off boost (twin-scroll or smaller turbo?). I used to own the 2005 C230 Kompressor and the supercharged engine in that car, while not as powerful as this one, had much better performance off the line.