Good afternoon ! A friend of mine was showing me his campaign and one of his behemoth was providing 350 % FIDSI production to one of his systems. Was he using a mod ? what is the max percentage the player can achieve with the FIDSI module ?

Could it be that was a stack of Behemoths?

A behemoth alone can generate max 50 fidsi with 35% fidsi bonus, tho you can stack infinite behemoths on one system. 

EDI wrote:

how can I stack infinite behemoths if there are a limited number of behemoths which I can build ? I have several behemoth techs and I can only create 3 of them because "you are able to build another behemoth each 3 behemoths techs researched."

There's a thing called C3 Centers that allows you to extend the limit, while also increasing the upkeep of the behemoths