My supercharger, M90, makes a rattling noise at idle and I found that with the belt off you can rotate the pulley on the shaft about 1/8 " before it seems to connect inside. If you rotate it back and forth quickly you can duplicate the rattling sound. It is not loose in any other direction and does not leak
Can I just remove the nose drive and replace the coupler and gasket or do I have to remove the whole supercharger to do this?
In some of the rebuild pictures I have seen there is a second section after the nose drive, with gears in it, that looks as if it is held on to the main body by the nose drive bolts. Will this be disturbed by removing the nose drive?

Not sure about the M90, but there are other benefits to removing the whole thing. It gives you a chance to clean things up, keeps you from getting SC oil all over the car, and really does make it alot easier. It'* not that big of an undertaking. The hardest part is coming up with all the parts. In your case, it will be a TB gasket, SC outlet gasket, 2 coolant seals (o-rings), and an O-ring kit for your injectors. It'* a good time to do all this. Wanna get by easy? Don't pull the TB. I'd suggest pulling it for a good cleaning anyway.

I bet I could pull the whole thing and put it back together in the same time as what you're proposing.

Some of us have become pros at this over the last few months. So if your not mechanically inclined dont be afraid to break it down because we are here to walk you through. I hope you live near a Pontiac stealership because you will need some factory parts. Or u will need to have the ability to order on line form GMpartsdirect.com. Lucky for me there is a stealership on my way to work and I had addtl rides so no hassle for me. I prob made 3 trips there b4 I was done.

I did it all with one trip to the dealer, and 4 hours of work. I win.

Thanks for the info guys. I think I might try to do it without removing the whole supercharger due to lack of time to work on it.
What type of sealer did you use as a gasket, and is ZZP the only place I can get the coupler?

I used the red RTV high temp silicone sealer. You can get the coupler from several places but ZZP'* is better than OEM. It'* made more durable and chaces of having to change it again are slim. Basically it'* made for performance. Withstands more heat.