plates are a personal thing and theres really nothing anyone else can say or advise that will appeal to you the way your own imagination will. jump on www.vplates.com.au and throw some ideas at it, see whats available. cuz most of the time if its witty, somebody else already has it.
Your car being an upgraded NA (GTS+t) is going to make things a little different than what Kris and Hamish have done to their cars as theirs were always turbo engines...an NA has a higher compression rate to maximise the power and response that that engine can provide without a turbo - otherwise people wouldnt buy them no point owning a skyline that drives like a camry lol. this is afaik anyway.
no idea re the Apexi turbo, but a dual SBC is fitted and tuned by a mechanic/engineer/specialist tuning shop to different power levels, ie setting one being 10, 2 14, 3 16, etc...whatever the engine and turbo are capable of without risking too much. really all you have to do as the driver is alternate between settings via the buttons on the control unit. but hide that shit cuz cops love them....
As far as power output goes youd have to dyno it to get a better idea.