Thank you all for the responses.
I am going to talk Service manage at our local dealership and see what she has to say about goodwill repair.
I thought of DIY, but I am still a newbee as far as DIY is concerned so don't want to risk it yet. There is always a first time for everything but I still feel bit nervous about DIY.
I am also bit pessimistic about getting a goodwill repair from snobby dealers. Having said that I am still going to try it out. As CALWATERBOY mentioned, as an owner of bmw car I feel it's my moral responsibility to report this issue --- which happens to be a very common issue for E90 firt gen cars and I feel it's BMW dealer/carshop's responsibility to give me a goodwill at least on the part if not labor.
In the end I might not get it but it's worth a try. I will keep you posted.