But....They rattle on bumps because the chrome strip is only attached at the ends, and the covers are only infrequently attached as well. The chrome strip rattles on the rocker covers, and the door threshold plate rattles on the chrome strip.

So I added some small screws (#4 x 1/2" are fine) along the chrome strip, down into the top of the rocker cover, where they would be hidden by the threshold plate when reinstalled. The heads don't interfere with the fit of any of the trim pieces.

Then I temporarily re-attached the threshold and marked the outer edge with masking tape, to act as an alignment guide for installing the EDPM weatherstripping next.

I attached some rubber EDPM weatherstrip molding with peel off adhesive to the top of the rocker, such that the bead would sit inside the pocket of the threshold. Fits perfectly!:



I put it all back together, pulled the masking tape, and no rattles! Nice and quiet now. And no new visible fasteners. Maybe I will come to actually like this widgetty setup after all.
