Rough idles are common on our cars. I have experienced it myself. But it all depends on how rough the idle is. If it is really rough (which I experienced while driving a demo back in 2005) then it is a vaccum line (which the dealer ended up fixing). But I have experienced an occasional stutter while sitting at a light. Never stalled or felt like it would.

Our cars are very unique... sometimes you notice engine noises. Sometimes you will hear a ticking from the engine. Lets face it.... they are noisy Mercedes. That is what makes our cars so special and unique. If you want a car that runs so smooth and quiet that you can't even tell if it is running then buy a Lexus.