I'd like to "me too" this. The M5-12 hex screw with steel washer did the trick. The reason this works is because the OEM screw tapers toward the tip, so it doesn't strip the deeper threads out as badly. You still need to tighten gently (you can't torque to spec!) and do use blue threadlock...

On my 97 wagon, I installed the IPD kit, and it fixed the rear panel but the trim around the rear window still rattles. It seems to be held in place where it inserts into the rear panel, but not tightly. I'm going to have to put some trim tape behind it. FYI, after installing the IPD kit, if you nee...