Hope it all works out for you mate, I am not in Australia anymore, I am in Georgia (Eastern Europe) I actually just got home from installing a Vipec GTS Plug in in a R33 GTST, I had it started and a mostly mapped in under 2 hours, if it was not for the boost issues this car is having it would have been fully tuned.
One day to do a 4d map? Damn man... I dunno what he is doing! I would love to know how much this tune ends up costing you, over in NSW I am sure you can get Scottie at Insight to tune your car for well under $1000 and I am sure he would only need the car for a day and one night only for cold start.
But ride it out, see how it goes.. Once this ECU is setup correctly it will be the best mod you have ever done for your car and you will think the wait and cost was definatly well worth it.
Good luck with it, let us know in a PM how you go with it if you can.
Anthony