This product performs best when installed over a subfloor before carpet, tile or wood paneling is installed. When installed on a finished floor it will sit about a quarter of an inch. The idea is that you can adjust the final height to work with any height of your finished floor. To easily remove the screw-on exhaust plugs, insert a quarter into the slot, then grasp the quarter with pliers and unscrew the plug. Overall, the installation was pretty easy.