Ive never known a car like it. For me it rattles because things fail, not because they are screwed down loosely or using thin connections etc.
When the (hopefully) shocks are replaced it will be smooth and silent.

What the heck did it need? I have a 'D' service coming up in 4000 miles. I was expecting £300-£400, not £1000+. For a small family hatch that is nonsense.
Our just rattles. It's been to two Merc dealers and both say there is nothing loose, nothing that isn't right, it's just how the B is - it's suspension is "crashy" and "noisy" and a million miles from my A4 in terms of refinement.
By "B" I mean A/B - it only has those two services - the "letter of lie" in the dash I still don't know what it correlates to - the dealer has quite clearly told me it only has A (Oil) and B (Oil plus a larger extraction of cash) services - with B notionally also including the "other" chargeable elements - such as the dust filter (that's £60 - though the filter seems to be £20 - and takes less than a minute to fit), air filter, fuel filter. The "oil only" plus minor inspection was £159 - and for that privilege they told me to clear off on my bodywork/rust claim because it had been repaired outside the dealer network (WRONG!).
The "B" which it is due next time, seems to be Oil+filter, plus the same list of checks - and I get charged another £100 for the luxury of the computer being re-set - and then I have to pay to have the air filter, "combination" filter and the fuel filter changed, as well as the brake fluid, and the Autotronic fluid change.
So - I'm counting on £259 (B service) + £159 - Autotronic change - and then £59 - brake fluid, and then the "other filters and things" probably another £200 - so coming up on £700 - which is quite honestly ridiculous.
(in contrast - my A4 - £249 - that's the major service, with oil/filter/pollen/air filter/fuel filter AND the MOT at the main dealer. £149 - CVT oil Change - oh and £49 for brake fluid so 450 vs 700 for what amounts to the same thing).
For some reason before taking delivery the wifes had a really big service. It was certainly all oils, filters, autotronic etc. and hilariously, given I'd said to the dealer I wanted to see the brake pad depth measurements before I bought, on the test-drive the "replace front brakes" warning came up on the dash so they had to have that done too - plus two tyres - but still can't see how they got to £1100, but he showed me the bill.....my guess is they inflated the cost to declare a loss on the vehicle - anyway.
AFTER delivery, well that's when the fun started. First winter, rear washer pipe kept coming off and flooding the boot, when it was cold, the car would struggle to start despite a good battery, and when it did it would sound like it was struggling to breathe, and was wheezing, the front suspension was crashy as anything, oh the list was vast.
When it went back, it was there for a WEEK! They had the whole roof lining down to install a rear washer modification kit, it had a new glow plug because one had failed, it had a new set of belts, it had partial new front suspension, god knows what it didn't have (but it DIDN'T have the thing they said they would do when we picked it up - I noticed a defect in a piece of trim, that they had in the warehouse and subsequently lost!).
A week later it was like a new car, no wheezing, started first time, all was well, and the rear washer worked properly without flooding the boot - but - still really noisy front suspension

I also note it's just noisy on the road full stop - doubly so on the Conti tyres that were on it (and were only lasting 10k on the fronts vs the 20k we've had out of the Falkens so far).
But then, the other day - the boot dropped. Having looked at the bolts they were loose, and one of them was mangled - probably when they had the boot off/roof lining out to do the rear washer kit.
I will say, that at the last service, the dealer replaced worn air-box rubbers FoC, and also removed and replaced the bolts holding the boot up with some threadlock FoC - which was good - but it's still small beer.
Overall, given the maintenance costs, and the fact it uses 2l of oil between services, and the faffing to get the rust sorted, I wouldn't touch Mercedes again....maybe I just need to accept the costs of sorting the rust myself and get a good indy to look after it - I don't know.
Cheers,
Dan.