The C-family is a little more important than the tiny GLA, so we should at least see one new motor, the 2.0-liter diesel. But the C43 is stuck in no-man's land between the regular models and the C63, which is the one everybody actually wants.
It probably wouldn't be the end of the world if the C43 kept its old 3.0-liter twin-turbo V6. I mean, Mercedes could even bump it up to the output it gets in the E43. Thought we forgot about that?
Anyway, the test prototype clearly has Designo frozen silver paint. No, it's not that cold in Germany to freeze paint, just a fancy scheme for Mercedes to charge you more money. A new diffuser at the back of the coupe might easily be missed, but the headlights and bumper can be identified from a mile away.
We mentioned that there was a second possibility, and that involves the C43 being replaced by something called C50 o C55. I love that last name!
Anyway, there's supposed to be a brand new 2.9-liter engine that connects to the past by being an inline-6 and to the future by using mild hybrid technology. That one is going to produce over 400 horsepower.
But there are two problems (see how this story is symetrical?). Firstly, a C-Class prototype with a brand new engine would look like it's been customized by MacGyver, with all sorts of measuring equipment. There's also no demand for such a thing, as BMW's upcoming M340i and Audi's S4/S5 are singe-turbo'd.