It's been almost a month with my new S-430 and it's been generally a very pleasant honeymoon. One issue at this point is the driver's side seatbelt seems to retract rather weakly, often leaving it to droop and get caught in the door if the driver (me) is not careful at pulling at it so it can fully retract.
I wonder if anyone knows anything about this?
Thanks,

Juding by the age of your car, I would simply take it to the dealer. Hopefully someone on this borad will give you some feedback, but with a car that young and for a car that expensive the dealer should be attentive to your needs.

I have the same problem on my '77 280E (W123).

In addition, one of the bars on the black plastic shroud that holds the metal belt tongue is broken.

I have been quoted an exorbitant price to replace the whole belt mechanism with a (non-MB) aftermarket item, which I really don't want to do.

Is it possible for a dealer to replace a spring in the mechanism (presumbly to speed up the 'return') and re-stitch in a new tongue assembly?

has anyone got experience of this matter?

Thanks