Did some research for people that will inevitably run into this problem:
BMW windshield glass is held to the body via urethane, the stripping or the "windshield cover" as bmw states it is simply there to block excess weather out of the grooves.
Windshield does NOT have to be removed for my trim job. I'm sure dealers will tell you otherwise.
There is also no adhesive, just a snug fit. What causes the accelerated cracking could be wax exposure to the rubber pieces which causes it to be more sensitive to weather changes.
303 aerospace protectant will help protect / elongate its life.
Part #1 51317210011 costs 30$ from my online searches. Will reply when i do attempt this diy. Seems easy enough.
http://blog.bavauto.com/6971/bmw-win...n-windshields/