Due to the fact I've no longer got my R53, I have one Intravee II & the Alpine KCA-420i adaptor available. The Alpine unit comes boxed and with instructions. Both units work perfectly and are as-new. The Intravee is attached to the KCA with a bit of velcro from when I had it installed.
Works brilliantly with both the Mk3 and Mk4 navs, probably others but that's my experience.