Said many times on here, not needed. If you want one, you can have my old HKS unit for free.

Any decent workshop (http://www.perth-wrx.com/vb/mechanicals/6775-perth-workshops.html) should be able to install it, or even an auto electrician place such as Deering Automotive might be able to. It is a similar process to installing an immobiliser in your car, as it hooks up to the same wires.