Use car parts are fine to use if you are like me! I like every thing new. Don't worry use parts in this manner are just fine. The only thing I would do is put white lube on your window track and door lock linkages. The only thing I wouldn't use is the plastic clips if you cant get them.
For brake booster rebuilds, the two with the best reputation are "Booster Dewey" and "Karps". Karps is the one I use. If you are looking for a source of rebuilding kits, I'm not going to be able to help you, as I've not run into a source for them. If you are a member of a club, post your question on there web site; someone will have an answer for you. WPC is the main Chrysler club, as you probably know, but I'm sure there is a 300 club also.
Some vendors advertise new heater cores on eBay all the time, so I'd look there first. I tried that on my 67 Imperial, and they couldn't help me. But I've found that a good radiator shop can rebuild and even rescore any heater core I've ever had to repair. I have gotten rebuilt power brake boosters for 64 Chryslers from AutoZone and from NAPA in the past - they are another source at around $100 exchange.
I can tell you my experience, I use Silicon Grease, and available at most auto parts places as it is designed for this purpose. It is clear grease in a tube, with a consistency similar to that of Vaseline, but without any petroleum content, so it will not attack the rubber or any plastic you put it on - it is totally inert in that respect.
It is used in space instruments for this exact reason and I've always used it on my cars -it keeps the weather-striping and rubber bumpers under the hood etc. just like new. I put it on in a thin coat with my fingers, rub it in a bit, and then wipe off any excess that might come in contact with someone's clothing. GE makes it, and so does Dow-Corning. The DC part number is DC-4. I got my last tube from the NAPA store - it was the GE brand, but it is just the same to use and the way it works.
I have a 1996 Jetta Trek with a door lock problem. The locking mechanism fails to actuate any doors other than the one in which I actually use a key. And, after using the key, I heard the vacuum pump running too long, as well as the telltale hissing which revealed a leak under the dash on the d/s. This all seemed to happen after I had a stereo system installed.
Running speaker wire, they must have inadvertently broke my vacuum tubing connector, right at the wire/air-line harness between the inside lower part of the d/s door and the chassis where it all feeds through the body into the fuse box area above the pedals. The tubing connector nipple (or what looks like might have been one) is sheared off, and I have two flush ends, which of course will not seal when I reconnect the harness.
Get some vacuum tubing from your local car parts store like they use under the hood on engines, and make sure it's just big enough to push that little plastic pipe into, but not so big that it slides right in. There shouldn't be a need to even glue it or seal it if the fit is tight enough.
