I'd contact people in the know reguarding engine swaps and other stuff like what type of cage, engine mods allowed etc, not too sure if this is done through CAMS or just ask through people at Rally.com.au Do this before spending a cent ok!!!
PS: I've been offered a driving position starting from August. Not sure what car the guy is planning on running but there have been discusions of it being an STi or early model EVO. Auctions are on this week some time so I should know by sometime next week!