You can import almost anything into NZ. When the restrictions were lifted in the late '80's all sorts of weird stuff was coming in from Japan. What they found was that JD vehicles meet Japanese Standards, not world standards, not even the pretty basic New Zealand standards of the time. Glazing, lighting, seatbelts, tyres, they all needed to be changed. This happens at border entry now, so they are compliant by the time of sale in NZ.
Back in 2006/07 I converted a MkII Jag to left hand drive...the owner was taking it to the US with him. If I converted a lefthand drive car to righthand drive here, there would be so many rules and regs, paperwork to smother me....it would end up very expensive all round. I guess the same would happen in the US. However, if I do it here, I have no hoops to jump through, just do the job, get paid and the customer takes his car away. It arrives in the US, lefthand drive, all factory, and what is not factory (the electric powersteer rack and pinion) is a compliant upgrade. Oh, I put a 4.2 in it as well, but again, almost a bolt in so nothing to look at too close.