Don't be tricked into replacing your entire blower when you could possibly just need to replace the supercharger coupler itself. A worn coupler will cause a rattling noise at idle that goes away when you rev the engine. This supercharger coupler will fit GM variant M62, M90, and M112 blowers. We have over engineered our coupler to provide years of trouble free use on cars with smaller than stock pulleys.
Below is a link to a video of a rattle that is NOT caused by the coupler. The rattle in the link is due to rotor rattle which happens when the rotor pack is bad.
To complete the job, you will need something to suck the old oil out of your snout, we sell a Supercharger Coupler Swap Kit that will make that pretty easy, which can be found here. You would also need new supercharger oil, which we sell here. (Most blowers will take 2)