can I setup a Russifier (mod that change language from japanese to russian) and run with it? or it's just can't be possible?

There is a list of approved modifications ( https://www.speedrun.com/gtavc/thread/w0b2j ) that you can make to your game. Anything not on that list is not allowed.

Makkebakke, thank you! however, I see this list before, but I wanna just asking to be sure that's not allowed.

You are allowed to use the official version from 1C released back in 2010. But since we're talking about modding the JP files then it's not allowed. Duh.