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I changed mine at Quill (which is an authorised BMW dealer in Malaysia). I am not sure if AB will do it for you but my recommendation is to do it at specialist workshop outside because it is much cheaper and reasonable. The only reason why you go back authorised is because your car is under warranty OR wouldn't mind to be charged unreasonably If you want, I can introduce my friend's workshop to you in Cheras. He used to work for AB and is very familiar with what needs to be fixed/done.