If you are looking for a Japanese import it is better to go with a car that is popular in the market. Personally I think you should try for Vitz, Mira, Passo in that order, if you want to keep the car for a few years.
Vitz is well established and new and old parts are available easily.
You won't find new parts for the Mira. But the advantage of Mira is that Mira, Move, Esse and Tanto share a lot of parts. The engine is the same in all models and a lot of other parts are also similar, excluding body panels and interior parts.
But whichever Japanese car you go for, parts will be relatively expensive.