depends on the RAW involved. most of the cars I have done from 2007-> now, I have pulled anything aftermarket OUT as it gave grief eventually due to scotch locks working loose. by rights anything imported after Jul 2001 was SUPPOSED to have an oz stds immobiliser fitted or have an exemption in the evidence submitted at the time. due to the amount of 'cheap' copmpliance work that was done a lot of the cars missed this point. if its not there and you have your car insured with a specialist insurer it may pay to read teh fine print. if you still have the dealer fitted one there - do our self a favor and get it pulled out before it strands you in the middle of no where.
@leon,
I'm not a charity , working on jap cars is how I make my living, - if you have something to say - say it, or forever hold your peace