as long as you have a stock air box,ecu,fpr (fuel pressure regulator) and stock exhaust you most surely will pass.
The only mods i had and were passed with were intercooler,gtr pump and after market bov.and they passed me,i think it was still a fair bit within limits and not so on the edge,as well.
You will need an engineers cert to pass this one.But remember that only the mods that you get passed will be road worthy.
IMO<<< ring the rta and book an emissions test right this second (tell them what it is for ie:you were fined by police and have to get a defect cleared.They will then tell you there are 2 places in sydney that you can get this done at.Botany or penrith.and you choose accordingly.i went by which one had the earliset possible time slot.which was 28 days away).If you want any chance of getting your car checked for the intercooler.You see,because the intercooler affects the inlet air thus affecting the emissions,in turn this is why they find the intercooler to be illegal.Your engineer will tell you that.
Did he ask you for an exhaust db test as well.I would definently get that done by the engineer while you are at it unless you have a stock exhaust.
Price wise,quite expensive.but any other mods after that,that you want to add to the list,are much more affordable.