silverado , I had completely forgotten about your experience and my response. My mind is going!
You know, the good thing is that we have a 12 year rust warranty. If this windshield replacement causes a problem, it will be before 12 years.
PS The other silver lining in this cloud is that by the time I hand the loaner 325xi back to the dealer, it may be properly broken in (it came with only 130 miles on it), and I'll be able to have some fun driving it. I'm being religious about keeping to the break-in rules.
I thank Wagner BMW at Shrewsbury (Massachusetts) each day for looking after me with this loaner.