First to make GB 3 you need the four main GB's plus Moranis and Potts. Weaver, Oscar, and Lenny can be reduced to camoes. I also had the idea of Saim Hain as the new bad guy, but he would be manufactured through CGI/Mechanical effects and his mission could be that he wants to consume all the ghosts in New York with his main target being the containment unit. The GB's should fight back using both old and new weapons. One of the new weapons should be the helicopter used in the RGB's. If we are to bring new GB's into the mix we need ones that won't cost the film to much money, since special fx's and murray's salery will consume alot. I would cast Christian Bale as the serious and psycho type, Tracy Morgan as the funny black dude, the cyclops actor from x-men as the smart and cautious GB, and Chris O'Donnell as the daring and cool character of the bunch. This one can be a bit darker then the other GB's, but still funny in its overall layout. No cartoony effects in this one though. I don't want to see a Mummy's Return shit here. The effects must have a realistic effect to them.