In my custom cab that I made that fits a 200S head upright, and a 2000S head on its side, and has a port at the bottom half the size of the bigger cabinets, an E140 fits fine front loaded, and has plenty of room with a standard 3/4" removeable grille cloth cover. I never tried to fit it into a 200S or 2000S cabinet from the back though. The E140's are freaking heavy, but they do sound good.
Greg