If you haven't already Hypo, talk to Keith from KCF about side intrusion bars and the recent problems with the Qld Police.
Also, decide on whether you want to keep the factory inertial reel seatbelts as that can determine hoop position and a couple of other things.
For what you do with the car, do you want the intrusion bars for strength (chassis bracing) or safety? I would imagine the chances of you going sideways into a big tree would pretty fairly slim?
Be prepared to strip the car bare before you give it to someone to put the cage in. I have heard of several people that spend ages trying to track down electrical gremlins only to find out that bits of welding splatter have burnt through wires and causing them to short out.
And once you get the car back, then there's the fun part of cleaning the cage and painting it.
And I wish I paid that much for my cage, If I had, I might have gotten a decent job of it and not have to fix up alot of it.