Since doing the repair on the left (Beetle door), I have found that Tyvek(R) house wrap makes great vapor barrier replacement (as seen above). I even taped it with the Tyvek(R) brand construction tape. The house wrap/tape procedure is faster and simpler, and probably better lasting than this procedure. The only hitch is that house wrap is only sold in huge rolls.
This procedure uses vinyl sheet that I bought at a fabric store.
Door Vapor Barrier
Replacing the plastic sheet that acts as a vapor shield inside the door. I'm getting pretty good at this. One thing to avoid: do not use butyl rubber. This stuff stays gooey forever. Bad idea for this particular repair.