I have in mind the Demon Tweeks version that uses a smaller matrix that plumbs into the OE pipework and this has a 3 speed 5kW fan unit behind it, Windows will have sliders both sides plus the small vent in the top of the rears. The OE set-up takes up half the dash and most of the parts are redundant, may as well start from scratch tbh. Not sure if a previously fitted heated screen can be re-used successfully, T16 has one, could swap them