1988 Century AC compressor vibration?

I have an 88 Century, when I turn the AC on I get good cold air, but the compressor causes a bad engine vibration and it sounds like a growl. There was a TSB for the problem, but GM told me the parts have been discontinued. Has anyone else had this problem? Were you able to get parts somewhere? Are Century's prone to engine mount failures? (could cause the vibration also). I took the vehicle to a garage that specializes in AC. They don't think the compressor is going bad, but pointed out that the engine has a bad engine vibration.

Let me know what you have already checked of these.
1. Top Front "dogbone" mount (a new one is less than $10 on sale at Pep Boys) and takes 4 minutes to replace. Check for loose or worn rubber.
2. Check serpentine belt. Is is in good shape, not cracked, glazed, or loose?
3. Engine stuff:
a. Check all vacuum fittings, hoses, connections for cracks, looseness, etc.
b. Check egr valve. They are not hard to clean, but you will need to order $5 or $6 worth of graphite gaskets prior to taking it off and carefully cleaning the carbon out. I like to use a shop vac to suck out loose carbon in the lines to keep it from haunting you later.
c. Use one a good injector cleaner one or 2 times.