The Alfa Romeo RZ (Roadster Zagato) was a very limited production sports car made in the early to mid 90's. A truly rare and exotic offering that it's highly unlikely that any were officially sold in New Zealand. Therefore, it would have had to have been a private import.
Alfa Romeo issues are similar to those of the period. Rust, electrics and unique parts availabilty.
If one of these cars appears for a WOF, ensure that there is no rust, lights are to standard, and the braking/suspension system is in tip-top order.
The car's unique construction and low numbers are sure to challenge serviceability wherever it is found world-wide. As such most parts - service ones included - will need to be sourced online, and mechanical assistance will require a true specialist. Be prepared for long lead times for even simple tasks.