Chattering Noise in SLK320 cabin

My 2001 SLK320 has a chattering noise that appears: 1. When the engine is fully warmed up. 2. When the car is accelerating. 3. When the engine is between 2500 and 3000 rpm. The noise sounds like it coming from a vibrating piece of metal or plastic. It almost sounds like a duck quacking.(No kidding). I cannot isolate the location of this noise. It may be coming from the dashboard, cabin, or even the trunk. It occurrs with the top up or down. Any suggestions?

Finally after 13 months, the dealer solved the problem. It was in the exhaust system. A technician told me this engine "resonates" between 2500 and 3000rpm, setting off the vibration. I am glad this was fixed, but not too optimistic about the future with this car.

[jjrodger]

My experience of our SLK230k is that this is not a rattle-free car. It is, however, a convertible and so that it rattles should come as no surprise. Otherwise we have had absolutely no problems whatsoever. The car feels particularly well-built, infinitely better than my very-soon-to-be-replaced C200. I shouldn't allow your confidence to be displaced by this experience.