OK, The dealer compleated the surgery: new cam chain tensioner and oil pump, verdict: KNOCKS EVEN MORE OFTEN! I think the "more often is because they changed the oil from 0/40 back to 5/30. I had the "Thats whatthese do at that milage" lecture when I picked it up. They say it is the Vanos system clattering but, what I don't understand is why wouldn't it rattle all the time, why just at start and why did it suddenly start after an oil change? Well that's my story, I now have 85,000 miles on it and it's too damn embarrasing to keep it because it turns every head when I start it up.