Well, to be honest I had to diversify crafts. Plasma cannons belong with the "alien" family, so it uses plasma cannons. Tormentor is with the "Earth" family, so it uses Gauss cannons.
I personally think it's rather debatable whether the plasma cannon is so much better than Gauss, considering its maintenance costs.
the range and damage is mainly why I wanted to put the plasma cannons on the tormentors.
is it possible to edit the files so that it can use gauss cannons and plasma cannons so there is a choice? or is it a matter of one or the other, cant have a choice? (EDIT: I answered my own question again. I played with the files a little and changed it so I can put either the gauss cannon or plasma cannon on the Tormentor and it works fine).
I mean, I fine it perfectly fine not to be able to put the plasma cannon on other human interceptors, but for a craft called the 'ultimate hunter' I just found it odd that you couldnt put the plasma cannons on it if you wanted to.
EDIT2: Is it possible to only build one Tormentor? I wanted to replace my three thunderstorms with three Tormentors but I cant seem to build more than 1 Tormentor.