Maintenance is no big issue with any Skyline really.
As long as the oil and filter is changed regularly along with a normal service routine they will just run forever if treated well.
I ran synthetic oil in mine changed every 5000kms but 10,000km intervals is OK under normal conditions.
Good thing about Nissans is a lot of Parts are interchangeable to many other models. For instance an R33 power antenna is interchangeable with a Maxima one etc etc....makes sence to do it but a lot of manufacturers don't .
If you're after new parts see Steve at Northside Nissan parts.
He knows and loves Skylines (owns a 33) and is also happy to import any Nismo parts you want/can afford.
Do you have a mechanic you know and trust?
If not what part of Perth you from so someone can recommend a local
Cheers
Chris