How much is supercharger rebuild?

I think vortech is picky when it comes to selling individual parts. They do not encourage people to rebuild their own kits. I know how to fix the volute but not the impeller. The kit I am looking at has a bad impeller. If they would sell it I would replace it myself but I dont know how to get one.
 
My pal sent his Paxton in for a rebuild and an upgraded impeller. When it was there they found a hairline crack in the housing and fix that too. It costed him about $900 and came with a year warranty.
 
The upgrade deal is for working chargers not bad ones. Also there is NO way - NO way he is gonna get $1000 out of a bad charger. Hell you can get a base 5-6 lb charger for $1800 all day long.