Search "Japanese used car" on Google and all the 1st page result are trustworthy having JAAI certificate. There are also some new reliable B2B sellers e.g. ***** who sell cars to dealers all around the world.
You can visit *****, on the homepage select Make and then you will find different model for that make. You can also select model code and color after that. I used to use this to know about the car variants.
Many people like you do not have proper knowledge on grading system for japanese used vehicles. You can read this article*******, surely this will help you.
Buying a car from a trusted dealer is the main thing, I guess. *******, they can give you proper guideline and they can work for you to import a car you want from live auction.