Does Supercharger Need Replacing?

If a "qualified" mechanic with experience with these cars tells me it needs a supercharger, why wouldn't I believe him? Take a look at the link.....http://buickforums.com/forums/threads/1596-95-Riviera- Engine-Noise-Vibration

There are 2 things to check and the first step is to remove the belt that goes to all the pulleys....do this with the engine cold, start the engine and see if the noise goes away. Don't run the engine for more than a minute without the belt. If the noise is gone....or sounds much different..... (1) check the harmonic balancer (this is the big pully at the bottom of the engine....it is mounted in rubber and often the rubber breaks and you get a rattling noise. (2) on the snout of the supercharger....close to where the tapered part bolts to the main body you will find a plug that faces toward the front of the engine...that plug has a HEX recess of an allen wrench (metric) find the correct allen wrench and remove the plug. This is an oil fill hole and you should have oil up to the bottom of that hole. GM has a special "snake oil" that cost about $7 for a small bottle. Add oil if it is low and with the belt back on the engine see if the noise is less. There are 2 bearing in the front of the supercharger and they do make kits to repair/replace them...check for how-to videos on the internet.