BTW, thanks for your input; I was doubting anyone would reply. Have you seen this screw-in piece anywhere besides NASIOC? Any vendors? Or would some kind of jury-rigged rubber washer (hell, even a bunched-up rubber band!) wrapped around the shifter bar (underneath the boot) hold it up?
The only place I have ever seen it is on my car. I don't know where to get it. I have heard of some people using a rubber band to hold up the boot and it seemed to have worked. Of course, it will dry up eventually.
Alot of people simply choose to buy a small piece of hose and clamp it down with zip-ties. Do a search on NASIOC or Scoobymods and I'm sure you'll find pics.
Really, anything rubber that will stick to the knob that can be fastened down will work just fine...