I can't really comment on what you get with a complete supercharger kit from someone like
www.capa.com.au because I bought individual fuel system / blower items from the States and had my own brackets etc fabricated.
After a lot of research, and talking extensively with other owners, engine builders and Vortech's own tech department I couldn't go past Vortech for reputation, quality, service and numerous sizing options.
I would advise that whatever boost level you're thinking of running, think carefully about incorporating an intercooler right from the outset. It'll give you an added safety margin against detonation, and more power into the bargain.