My W213 had developed a rattle upon acceleration, a really noisy grating noise which was impossible to ignore. I only noticed it properly on Sunday as I've not really had chance to use the car much due to real life getting in the way. Yesterday (Monday) I had to use it and it was getting frustrating so I called into my local dealership on the way back home. Brilliant service as usual, waiting no longer than 10 minutes till I was met by a mechanic who I took on a very short test drive. He agreed instantly that there was a problem, so we brought the car back, took it straight into the garage and put it on a ramp. As soon as it was in the air it was obvious what the problem was. The exhaust was practically touching the cross member underneath it with a gap of around 3mm. There were some very slight marks, though nothing detrimental. They didn't have time to sort it yesterday though I got it booked in for first thing this morning. The same mechanic took the car in, removed the cross member, cut a bit out of it for clearance and shimmed the middle bolts out with a couple of washers for even more clearance. Another quick test drive with him driving this time and me listening and all sorted out. It's a job I could easily have done myself, though by letting them sort it my warranty is still intact. As this seems to be a design fault, they're expecting a few more in the next few weeks, though I was told that, at least currently, nobody else has complained. Incidentally, I prefer to refer to the guy who fixed it as a mechanic and not a technician/fitter, as he fixed it using initiative and a few old bits and pieces, and not relying on plugging it into a computer.