Well, I've gone and done it now. We had to replace the pilots side door on our 170 (an old repair on the lower back edge was falling apart) with a "new" door, and then paint it to match. After stripping the door and putting fresh paint on it, I just couldn't put the old, nasty brown vinyl and carpet-over-aluminum door panel back in. I called Selkirk and ordered enough 1/4" insulation to do the door like Rob, Matt, Big Renna,and others have done. We went a slightly different route, and so far I like it. I present you with Selkirk Insulation Door Install variation 2:
Originally we planned to cut out the four holes and put insulation rubber behind, but after cutting the outside dimensions on the rubber we laid it over the door to check for fit, and I liked it. We'll see how the rubber over the holes holds up - we can always cut the holes out later if we decide to. I also replaced the door handle with a brand new one for a 40-48' Chevy for $20.
So now we're getting more paint mixed up and we'll do the passenger door next. Then on down the rabbit hole. I didn't have anything to do after work for the next 6 months anyway.