Thanks for all the help in tracking down the right part numbers. I went to the Long Beach BMW "parts palace" (boy, is that place nice!), and a nice gentleman named Ron helped me out. He knew what I was talking about once I showed him Jon's photos, but he was unable to track them down in the computer until I showed him Perry's partial part numbers (say that 10 times fast ;-)).
We were chatting about all the BS I went through with McKenna BMW and he even gave me a discount: $16.50 each (two total.) They'll arrive on Tuesday.
Bravo to Long Beach BMW for good service! Bravo to this discussion board for assistance.
And finally, for the archives, here's the part numbers and official names of these "thingies."
Air Duct: 51-71-8-398-827
Air Duct: 51-71-8-398-828
One for each side, of course. These are the numbers for what have been called "lower air dams," "lower air ducts," and lower "cable guides."
Hope this helps,
Esmerelda's Pages ~ Z3ers.com