I "exported" my car to Spain. A good move financially as the cost of acquiring a car here are high (both residuals and transfer tax). Like in NZ people here drive the car till it/they die.
There have been many times I wished I hadn't brought the Omega much as I love it. Getting spare parts, despite there being Opel dealers is difficult as they are few and far between. Scrap yards (I have seen) don't have petrol Omegas in them or diesels for that matter.
You may be able to get parts via say EBay Uk, but not all sellers ship worldwide, but my advice would be not to take it. Get a local car instead. If you do insist on taking it then I would go over it with a fine tooth comb and get it up to A1 before setting off and then take all the parts that seem to go on the car. You could ship these stowed inside. e.g. exhaust system.
Exporting a car is straightforward enough via DVLA but I would check there aren't any undue costs at the other end other than a local MOT, inspection and NZ plates.
varche