How much time and cost is involved to install a rebuilt supercharger in a 1998 3.8L Buick Regal?

Places like superchargersonline sell complete rebuilt superchargers for around $439.00 and they come with all the gaskets and everything needed to put them on. They also come with a lifetime warranty. Usually there is around 2-4 hours labor involved so most repair shops will charge around $200-$400, to put them on.