Call BMWNA. On my 330i SA told me that BMWNA did not authorize any work at all, including the HVA replacement, because the technician could not replicate problem. One quick call to BMWNA, and my SA calls me back an hour later saying that their technicians now can hear the noise and are going to fix it per the SIB. I've had the car back for a couple of weeks now and I don't hear the noise anymore, so I didn't need the new cylinder heads, just the HVA.

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2010 X5d, Space Gray, Tobacco, Premium, Tech, and rear climate packages, roof rails, spare tire, and iPod adapter.
2006 330i, Sport, 6MT