The Mercedes-Benz C-Class (W205 generation) marked a major stylistic and technological break from its predecessor, adopting the aesthetic codes and finish level of the S-Class (often nicknamed 'Baby S-Class'). Based on the modular MRA platform, it shed about 100 kg thanks to the extensive use of aluminum. The 2018 facelift brought 100% digital instrumentation, new driving aids, and, most importantly, a complete overhaul of the engine range, notably introducing the excellent OM654 diesel engine to replace the aging OM651. Although very luxurious, the first model years suffered from some teething problems (interior trim noises, electronic bugs).
The Mercedes C-Class W205 is an excellent road car, but it requires selectivity. If you are looking for a diesel, avoid pre-2018 models if possible (noisy OM651, somewhat underpowered OM626) and absolutely prioritize a facelifted version (post-2018) equipped with the OM654 engine (C200d, C220d, C300d). This engine transforms the car, offering cathedral-like silence and negligible fuel consumption. However, be mindful of maintenance costs: steer clear of models without a clear service history, beware of Airmatic suspension out of warranty, and budget for the inevitable quirks of the AdBlue system if you drive in the city.