I am not a mechanic but I too have a 96 buick SC and my
supercharger was bypassed by my ex (big retard!) and I went
without it for 9 months until I ran into a real mechanic who told me to
get it hooked back up. He stated that the engine is designed to
run in conjunction with the supercharger engaged and without it your
overall performance is compromised. If you go too long without it
running, the supercharger itself will freeze up and will have to be
repaired or replaced and I have done the research on it and most
mechanics don't even want to touch it without a hefty deposit. My
advice to you is: If your supercharger is okay, replace your damaged
pulley and the two others with new ones. (the new pulleys will not be
plastic and will be more durable and you won't have to worry about
replacing them later) Buy a new belt and get it hooked back up. I
was also informed that without your supercharger, you are restricting
your air flow to your engine and causing poor gas mileage. I took
my friends advice and replaced all pulleys, put a new belt on and I am
completely satisfied with the improvement in preformance of my
engine. Besides, I love my car and who want's to drive one of
these sweet rides without that extra power for when you need to do some
quick passing on the highway? LOL I hope this helps.
PS. My overall parts cost was about 100.00 for all three pulleys and
the belt and I paid a friend to put them in. I got off cheap with
the labor because I didn't take it to a dealer ship. My advice is
to find a local mechanic who had done this repair before so that he
knows about the brackets that have to be removed. This took him
about 3 hours for a first timer. But, he also accidentally broke
a bolt off when he was pulling one of the tensioners off and that added
some extra time of boring it out. Good luck with your car.