Oh, well, I can't pretend to be pure; I have rigged up worse things...
but, but, this is a freakin' Mercedes-Benz, ya know? I gotta maintain the illusion to justify the parts and trouble.
I am repadding the center pillar covers with polyester blanket padding from Hobby Lobby. The original foam rots with age and heat and crumbles, and wrinkles show up. It's a pita to glue the vinyl back on, but the padding is just right when you get it all together. This is a rig-up, but it is sort of an engineered improvement, since I'm an engineer...
Polyethylene it is, then.