There are plenty of places in Aus or NZ that sell at far lower prices than Europe or USA, but they're not really allowed to sell outside the country.
Motec Europe or Motec USA won't provide support to grey market imports and if you ask Motec Australia for support and they find out you're in Europe or the US they will tell you to contact your local Motec branch, who will either charge you a fortune or more likely refuse to support your ECU.
The only way you can get support is through the agent that you bought it from and not many of them will do this for foreign customers. You really need to get someone local to purchase the ECU and relay any support queries. Good news is that Motec needs very little support and failures are rare, but you'll need to find someone who is prepared to act as a middle man
Depending on which ECU you want, base maps shouldn't be a problem, changing injector size in a Motec is a simple job that takes about 1 minute so any 3S-GTE with the same mods should be ok. However it would only be a map to get you started, not one that you can drive hard on, you would still need to get it tuned for your engine.