Don't they feel a bit short of power on high speeds on the autobahn?

I'd agree with that. I recently drove a 2007 CLK200 Kompressor on an 800 mile round trip to Holland via northern France and Belgium. Most of the journey was motorway, and I found that when using the cruise control the car would need to change down - often two gears - just to resume a set speed of 80mph or so, even after slowing only marginally to 72-75mph.

It was gutless, but to be fair to it it did manage around 36mpg for the whole trip, with two adults and two kids on board. Whilst they're obviously poles apart in terms of performance, I'd be lucky to get 26mpg for the same journey in my S4.

Around 160 km/h they somewhat run out of steam. They also get really loud at that same speed. However the economical cruising speed of those models will most likely be around 130-140 km/h and the noise levels are still very low at these speeds.

I guess if you're picky about that you're better off with a C280 or C350.

Maybe the wannbe owners are doin changing the grille themselves at least here they do so,saw a couple of C200K elegance models with the avantgarde grille and when i asked the owners they told they did it in the service center,i hate when people do that