Well, my car is being serviced now for this. Same problem, the hydrolic lifters. I don't know why BMW is so reluctant to issue a recall for this. They really should.
If I hadn't have seen these postings on the board, I would have never thought much about the ticking noise. I thought it was just an occasional quirk.
If you hear the ticking, take your car in. Perhaps the more people that complain, the more likely they will issue a formal recall.