Sorry you're having a hard time finding information.
Most people on this forum are from English-speaking parts of the world. In those markets, the Mirage is very much an underpowered econobox. Parts are also fairly expensive. You will find very few people here who have ever eyeballed a Mirage with performance tuning in mind.
There does seem to be a decent amount of Mirage tuning going on in the Southeast Asian countries the vehicle originally targeted. You won't see many posts about that here, though.