Yep that’s the stuff! The oem weatherstripping has a metal backing, get your fingers behind that and pull it out, then stuff the foam rope behind it. I went from my finger to the black road grime spot above the weatherstripping (or the White string hanging from the ceiling in the background). It was such a large gap between the door and oem weatherstripping that placing the 3/8” foam rope in there didn’t even push the door out beyond the rear door when closed! Still flush as you can see in the pic from outside the truck with doors closed.
I also did this on the bottom of the door and to the rear doors where I saw that the oem stripping was not rubbing on the door.
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