this one would be straight forward - you buy it - send 2 pics of it, the purchase receipt and the following forms to dotars (dept of trade etc) -using their application form

which u can download off their web site - under the pre 1989 vehicle import scheme - using the relevant form

it isn't modified and has no air cond so that's good. It will cost u as per attached - but the exchange rate is now essentially $ for $. You will have to pat GST on the car and import costs.
best to take it out of Christchurch - I have a guy there who can organise it