Well I stopped by my friends at Open Road and they concurred that there is no primer necessary on a repainted bumper. Here is what I learned. Remember my replaced bumper is Alpine While over Flex-Prime, so all that is needed is to rough up the paint to eliminate any shine, remove any wax, polish etc, and she's ready for painting. I hope to have it done this week so it'll definitely be ready for the CT Get-To-Gether.Also BMW bumper specific paint is "rubberized" for flexibility. The bumper cover is actually mounted into a system designed with horizontal shocks, and the sides are held in place via tracks on both sides, thereby giving it some movement horizontally.
See the part indicated as #4. It has the ability to "slide" inside a track, again adding to the flexibility.


Only time will tell...
Ed in NJ