If it has a good service history and you keep the maintance up chances are you wont have to fork out big to keep it going. Ive been running my vr6 making $70 a week, and have spent most of that on little mods (manage to scab fuel money from parents/friends ect when im taxiing them around which is like 80% of the time). If (well when i guess, you have to be ready for it) things break the actual parts for most of the things are actually pretty cheap (like heatercore is less then 50, timing chain kits are only a couple hundred, same with clutch), its the labour that will rape your wallet. Theres a lot of information out there about how to do practically anything to the vr6, some good detailed guides on timing chains ect, so really if your willing to get stuck in, spend some hours swearing and trying to figure out wtf youve done wrong and learn a heap about your car, you can fix most of the common problems up pretty cheaply. Dont let the horror stories put you off. Do learn from peoples mistakes though (eg, if timing chains are reallly bad, dont keep driving till it slips and destroys valves ect)

I got my VR6 from Sydney aswell, id recommend printing out a few adds and taking a look at a couple if you can, incase the one you're really interested turns out to be a no go. I guess NSW->QLD is a bit further then to VIC and we spent a weekend there and did a couple other things aswell, but came home with a completely different vr6 to the one i had basically planned on getting (it was sold days before our flights where booked...)

Good luck!