You may have more regional specific knowledge if you post on the Australia/New Zealand forum, though your post is very welcomed here too.
I have no knowledge of the import requirements, so I'll leave those comments to someone else.
In the mean time, I very much enjoyed Tomahawks when I flew them. That said, I believe there are life limits on the airframe, so make sure you are familiar, and considering such limits on the price you might pay for the plane. Also be familiar with the the availability of repair parts, as these airplanes might not be as well supported as you hope. I'm not saying anything bad about the plane, I liked them, but legacy planes are not so well supported now, and aging airframe concerns are attracting more attention. Make sure you know what you're buying into...