Hi crystalworks,
I bought this factory part. Comparable price to all others and I have used this seller before and they ship quickly
https://www.ebay.com/itm/For-BMW-Gen...3/362548211955
Sure glad I didn't have to buy all four of them!
The leak was odd, It was not at the hose/o-ring interface and it was not a cracked body since I blew in the headlight facing end with my finger over the nipple and could not detect any leaking air.
Mike