Fairly sure US uses different frequency spacings, so unless the radio can be set to NZ, then it won't work.
FM is spaced 200kHz apart there on the ones with a odd number after the point, so 88.1, 88.3, 88.5 etc - that contrasts with the arbitary spacing used in NZ ending on anything. Preemphasis is different but with the trash sound and overprocessing on FM here, I dont think you will notice anything there.
AM (if there is still anything on it where you are) is 10kHz there, and its 9kHz here.
If it relies on can bus support for vehicle speed etc, that will probably not be supported on a non US model as they have quite strict standards on protocols for the OBD2 connector, where as the rest of the world doesnt have to support all the things that are mandated in the US.
Correct, the radio will be set to only pick up 98.1,.3,.5 etc, no .2,.4,.6. You can buy a .1 band expander, but apparently they don't work very well. If you don't care about radio they work fine. I've imported a couple before.
You've already been advised about 0.1 "band extender". What you need is technically speaking not an "extender", it is frequency shifter for 0.1 But it is only needed in Auckland. In Wellington or Kapiti FM will work without modifications. And if you install one and travel AKLD - WLGT - you would need the switch - i.e. shifter on/off.
I've got schematics of the one which was tested and worked good. But components required are hard to source (not available on eBay).
See if you can get the service manual online. There might be a jumper on the main board to define the spacing (amongst other things) or could be a button combo.
Since both regions have the same band the main micro chip and tuner pack are probably identical across the regions.
Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21
I had a 2 DIN Kenwood radio from Japan ( we bought the car in 2006 so some time ago )
All I had to do is lift the lid and move a resistor, it was clearly marked 76 - 90, 88 - 108 50 and 88 - 108 75.
I moved the resistor, powered it on and it worked when promptly dropped the screwdriver and blew the bloody thing up.
Not all of them are that easy, most cant be changed as the US and Japan are a big enough market to have their own product.
Australia has the same AM ans FM specs as us so you would be fairly safe there.
I know enough to be dangerous