Pontiac Repair: Supercharger, newer cars, 5k miles

Question
I have noticed that on my 2004 GTP (3.8 SC with 65K miles) that it sounds like the supercharger continues to spin for 1 to 2 seconds after I shut the engine off. While driving, boost still seems good and there are no unusual noises.  The belt was replaced about 5K miles ago.  Also, I change the SC oil yearly.  I've never noticed sound this before.  Sort of a whine of something spinning-down. Is this normal?

Answer
Hi Craig:

The super charger stops spinning as soon as the engine stops. If the belt is not spinning the super charger shouldn't be spinning. If it's not making an unusual noises then I wouldn't worry about it. If it starts to make noises then look further into it. Other wise I wouldn't worry about it at all. These ones on the newer cars are prettyy reliable and done break like the previous generation ones did say 1997-2003.