Welcome Al. Can't wait to see another 370GT on the road in Perth.
Since it's still a newer car, the information will be hard to get sometimes. Don't worry, it will change in the future.
All I know of basic mods and (maybe) add a few kW are good high-flow panel filter/CAI and a full cat-back exhaust system with high flow cats. Maybe you can get a good quality coilovers and lower the beast.
I think US/Europe Infiniti models's system are in English. I saw one convertible Infiniti G37 at Fabcar in Cannington and it was all in English, as it was imported from UK, not Japan.
Good luck with the import. Come along with other V-series owners sometimes later, as we are eager to add newer V-series to the group in the future.