Not sure what the government taxes are in NZ for importing cars, but that is usually where it will hurt the hip pocket. That and the conversion, especially near new cars with all the saftey air bags and equipment!
There certainly are sites that will sell you there data base info, but one of the best free sites is Link hidden: Login to view
for my money.
Not sure where you are wanting to import from, but if it is the US, then I would suggest you talk to DAS Link hidden: Login to view
They are reconmended by ebay as their preferred carrier, and I'm sure they would be really helpful with your shipping information.
Good luck with the venture