Welcome Keith! Nice to have a rep here! I was just reminded of a question I need to ask Tire Rack, which may also help others.
I purchased a set of O.Z. Leggera HLT 18x8 wheels and 235/40r18 MPSS tires from Tire Rack for my M235i last September. They came with the standard carbon fiber O.Z. center caps. I was looking on O.Z. Racing's website some time ago and noticed something on the Leggera HLT spec page.
http://www.ozracing.com/wheels/oz-ra...ch/leggera-hlt
Note the line that says OE Cap Ready, indicating Porsche and BMW. I contacted O.Z. Racing on twitter and inquired if they knew of a specific center cap (they must, based on their website), but they told me to contact my place of purchase.
So my question is, do you know what BMW center cap will fit these wheels? Is it something Tire Rack stocks? I don't really mind the carbon fiber ones, but would rather have a BMW cap if possible. I have searched dealer/parts sites and haven't found anything that looks like it would be a compatible diameter yet.