I'm thinking that mine have gone, although at the moment the ride isn't majorly affected. Current behaviour is that under 'reasonable' weight transfer/acceleration I hear a knocking/creak at the rear, and during spirited direction changes the rear end definitely feels broken (the springs don't take a set, they bounce waaaay too much).
Annoyingly the problem happens at around 8pm on 29th March 2010. My warranty expiration date? Yes, 29th March 2010.
Went to the dealer on 30th March and it's booked in but is definitely 'out of warranty'. If a change is due I would hope that it would be easy enough to get them covered under a goodwill agreement (especially as they failed under the warranty period, although of course I cannot prove this).
If I can't get them covered I'll probably take the hit and go to Eibachs or similar (although I don't really care / want to lower the car). I take it Eibachs won't break as easily as the poor BMW offerings?