Pg 192 F&D under "installing mods"
I think I may have been doing this wrong, since my EotE game. Do you have to roll individually for each mod? Gradually increasing the diff as they add more mods? Or is it one big "winner take all" roll at the maxxed diff?
I was doing one roll for the whole shebang, assuming they wouldn't want you to make so many rolls. The way it's worded though, I think I may be mistaken.