Supercharger will have a sound like rocks tumbling around in it if the coupler is bad and will have a sort of low pitched grinding sound if the case bearings are bad.
For the most part, the major issue with the supercharger is the coupler. If you are comfortable turning a wrench, you can fix it, its a time consuming but easy job. I dont know what to tell you with regards to mileage they can go bad, they really dont for the most part. The coupler, the case needle bearings and the coating on the rotors are the only issues. Even if the coating on the roators comes completely off the worse you will see is reduced efficiency that will translate into slightly less boost.
I have a complete spare supercharger in my garage, case, rotor pack and nose drive and Im certain I paid no more than $150 for it all if that. Prices will vary but you should have no problems finding a replacement if it were ever needed.
Tail light is easily enough replaced, you can generally find those in classifieds or on ebay pretty frequently. Someone already posted a link to an ebay auction for the window motor, paint chipping I would expect some of on an 11 year old vehicle. The rust is the major thing for me. That I would have taken care of as it is only going to spread. Thing of the moisture you splash up in there during a rain storm, washing the car or even during winter when you may encounter road salt getting up in there.
