... Half the enjoyment I get from this hobby is learning something new and being empowered by knowing I did fix it...
I won't get into what one person can afford vs. another side of this thing - but I totally agree with the 'fix - it - yourself' credo!
I used to rebuild my own compressors for years, and there's really nothing tricky about them if you understand and can do resonably good mechanical work, follow ALL the instructions during your work and are careful with the "fine-points" during your assembly.
The biggest 'hint' or tip I would give someone when reassembling one of these is NEVER-NEVER-EVER touch, wipe or any other way make ANY contact with the sealing surface of either one of the seal halves during installation EVER!
These seal contact surfaces are very delicate and precision lapped to each other during manufacturing, so they seal quickly after the first few turns of the shaft. Even a slight rub or touch to the surface will leave a minute scratch that will lead to a leak! I would be will to bet the re-manufactures guys give them the wrong treatment during install and that leads to the leaks...
It is also very important to cycle the compressor to bed-in the seals, pistons and bearings prior to installing and charging the system for use.
These procedures are outlined in the GM Service information and were covered in a great article in Hot Rod magazine a while back - I'll go hunt for the article and link it if I can find it.
(edit) - found it in he first search, that never happens ... - http://www.hotrod.com/howto/7954_air...ild/index.html
If you can't do this type of work, then deal with a reputable outfit (like Classic) for your parts and you will have recourse for problems.
As always JMHO's