Watch 2019 Mercedes CLS 400 d Accelerate Smoothly Past 250 KPH (155 MPH)

In the recent past, that meant nothing because Daimler wasn't a big player when it came to diesel engines. It only really had one good V6, which it fitted to everything from taxis to the G-Class. But thanks to the newly resurrected inline-6 architecture, there's a variety of 3.0-liter units, which match or sometimes exceed the output of their BMW and Audi counterparts.

Maybe we should have called it a 2.9-liter since that's how you're supposed to round out 2,925cc. In any case, the most powerful version is found in this CLS 400 d, and it produces 340 HP plus 700 Nm of pulling power. Right now, the S 400 d is only identically equipped model, though others will be available soon.

With a 0 to 100 kph (62 mph) time of 5.0 seconds (officially claimed), the 400 d configuration is supposed to be 0.2s slower than the 367 HP CLS 450. But that's probably not a deal-breaker, especially as the weight of the two models is identical and fuel economy heavily favors the diesel model. It's supposed to average 5.7 l/100km, about the same as a MINI Cooper S.

The acceleration video below is shot by AutoTop on what we presume to be the autobahn. While the 0 to 100 kph was actually timed at 5.6 seconds, the car's performance after that is what impresses. There's a constant surge of pulling power that takes it to 250 kph (155 mph) and a little above that.

The sound inside the car is noticeably better than what is shown from the outside at the beginning of the video, which tells you it's fake. However, the CLS is not about being a sports car, a sideways V8 German 4-door. It's all about looking good in an expensive-looking Mercedes. And now, you can have performance and fuel economy mixed into that package as well.