Thanks for the replies.
I went with ECS, and bought the OEM sourced cold weather oil separator kit. I looked at a few different suppliers, many only offer URO brand parts, which I will not use based on my experience with anything from them for the many M-B's I have/had.
I spoke with a rep from ECS who verified this kit uses OE BMW components, hopefully so! I also learned my 2004 is VIN specific for the CCV, early vs. late production; mine being late, it of course uses the more expensive separator.
