Just replaced my oil cap...
After having the second OEM oil cap leak on me, I have now gone to the new design. I honestly don't know why BMW even sells/stocks the original design since it sucks and the new one fits. Totally bizarre to me. The new design is noticeably tighter on the valve cover.
Original from my 09/08 build MY2009 M3: 11127832157
New part I just got from getbmwparts.com: 11128507153
Hope that helps someone.