supercharger

I took my car in due to a rattle under the hood.....They say I need a new supercharger.....not what I wanted to hear....Anyway, my ? is this....are there some common parts that can be replaced w/i the supercharger, or does the entire s/c need to be replaced? Also, with the s/c going bad, would that cause the idle to slightly go up and down while in gear and stopped (especially when the A/C, brakes, blinkers, headlights, are/is being used)????

Most shops will tell you that the supercharger needs replacing to cover themselves for warranty purposes. However, I've found thru research on this and other forums, that many times the problem is simply the coupler in the S/C cone. I replaced mine myself.
Checkout thread http://www.automotiveforums.com/vbulletin/showthread.php?t=408223

There is also a link to another thread within the above mentioned thread describing how to replace the coupler on later model superchargers. Actually, it appears some models have a belt dedicated to the S/C that can be removed to verify the noise is from the S/C. However the belt on my `95 also runs the water pump so this was not an option for me.

What ever you decide to do don't make any decisions until you thoroughly researched your option. There is a wealth of information on the internet regarding this topic.