It fit in perfectly. No modifications needed for the closet flange, nor for the water hookup. What you see in the picture is the complete toilet (base included). It was a simple matter of unscrewing the water hose in the back going to the old toilet, removing the two nuts holding the old toilet to the floor/closet flange, cleaning everything up, and then reversing the process with included new bolts with the new toilet. Don't forget the teflon tape for the threads on the water connection.