Heads up on PCV conversion
 

I did the PCV conversion on my (wifes) recently purchased X3 M54. Full manifold vacuum to engine seemed a little alarming but I realized that my E30 M20 was full vacuum as well and seemed to work fine. However after a few weeks I noticed that the vacuum has dropped way down, I'm guessing to about as much as it would have with the factory CCV. My guess is (and my fear originally) that the rear main or front seal outer lip got sucked in or worn out from the vacuum sucking it to the crank. Sooooo while I like the idea of getting a little fresh air in ( I actually had installed a small orifice and filter to let some in) there it is now a lot getting in and it's not filtered. I think it will all be OK but I wish I had done things a little differently. So just wanted to let others know what might happen.

Did you get any codes? I did conversion and it is over 24k miles with no issues!
In my case, when vacuum plug in the side of the intake manifold developed small crack, I got fuel trim codes. Check your fuel trims and inspect those two hard to reach small vacuum plugs on the side of the manifold.

My USB OBD cable bit the dust so can't check any codes at the moment. I don't have an intake vacuum leak though, manifold vacuum is fine, I have a crankcase air leak. The guy that posted the conversion with pics said that he had very similar vacuum(in the crankcase) after the conversion as with the original CCV so I imagine he (and many others) have the same problem. I would be curious though as to exactly what "let go"