I don't know if you did your door pins yet, but I recommend OEM GM door pins and bushings only - still available online or at your local GM dealer.
They come in multi packs, so I bought multiple sets equivalent to the pack size and sold the remaining pins/bushings here in the for sale section.
I have a thread on my pin and bushing install if you search for it - might help you find a good source.
Speaking of sources for OEM, I like:
www.oewarehouse.com
www.oehq.com
www.davesauto.com
www.gmpartsdirect.com
www.rockauto.com
Also, search ebay and Amazon once you have the OEM part number.
I have purchased parts from all of these sources and have had no problems.
I have no cherry picker, so I built a short platform out of old 2 x 4 s to support the door bottom when removing and reinstalling the doors - worked good for me.
New pins and bushings made a huge difference on door closing. The power door lock and window wiring had to come out but it was not too much of a hassle.