http://www.ludespeed.com/impreza.html
There's where you can buy a kit. What more do you need?
http://www.forcedairtech.com/ - there's another
edit: heres a used Ludespeed stage 2 upgraded to a stage 3 with the injectors that no longer come in the kits for $3000, great price!
http://forums.nasioc.com/forums/show...hreadid=414633