From what I have read from Zex, this new 05 GT (new fuel syatem) requires another component but Im not quite sure what that is, it may just be a redesign.
I would think so. If you have to get a tune for an air kit, I would think you would need a kit to spray nitrous. I would, just to be on a safe side, plus, it will optimize the mod. So safer, and more power out of the mod.