NZ gets most of Japans cars when they are five years old, so "Jap imports" are standard. It's a combination of having no import restrictions on cars and being right hand drive, along with Japan making it very expensive to register cars older than five years.
BUT - Silvias are wanted by boy racers so they are stolen all the time, and because they are "project cars" they are way more expensive than most other jap imports. For example this old 1990 one is NZ$5000 - if it was anything else it would have been dumped years ago. American muscle cars on the other hand are serious wedge - say NZ$100 000 for a Corvette Stingray