G'day mate and welcome...Check the events section for meetups etc. Quite a few gtrs normally turn up to cruises and meets so if you are after a ride in one you can ask an owner who posts that they are turning up.
As for the above....xenons, passenger/driver airbag were standard in the series 3 R33 gtrs and of course all R34 gtrs. As for cruise control thats a no (pretty hard to get cruise control in a manual and all gtrs are manual). Also AFAIK no sunroofs were available in a GTR.
As for what to look for.....importing is a bit of a mine field as you don't know the history of the car and cannot get it inspected prior to purchase. Much easier to buy one in Oz and you can take it to a respected workshop such as racepace for a look over prior to purchase. As long as it has been looked after by previous owners...regular oil changes, quality mods and maintenance etc you can't go wrong keeping in mind they are well over the 10+ year mark.