Just wanted to report back. I did end up going with the BMW part in spite of the cost. The old one broke in the exact same place it seems like they all do. I fixed it with the steel zip tie per @andrewwynn's excellent DIY writeup and it's on the parts shelf ready to be swapped out if ever needed.

Thanks to all for the good advice! On to the next repair now. :-)

Chris
Lockhart, Texas
2005 X5 3.0 Schwarz Black
2002 X5 3.0 Titansilber