In principle this is an excellent modification - BUT - beware; this was designed for a left hand drive installation and installing on a right-hand drive car causes some interference and access issues. I was not impressed by the rough and 'heavy' sand cast finish or the simplistic video on ILM's website I must say. No instructions came in the box but the video does highlight a couple of things that you must do. If you didn't know about the video you could miss them.
I decided to do this mod whilst the head was off for a change of head gasket. Access to the rear of the head is imperative and on the MX5 it is not good as we know. Whilst there I also removed the rubber blank, and its pipe, and drilled and tapped for a shortened bolt. When I installed the studs in the replacement body they did not quite line up with the holes in the hose outlet/thermostat cover and I had to gently elongate the holes. Not exactly the precision German engineering I was expecting. This cover has to be installed after the head goes back on otherwise you cannot get to the single wire connection to the temp sensor.
The cover then fouled the clutch hydraulic pipe which I had to gently bend (not easy being a steel pipe) until sufficient clearance was obtained to install the cover AND install the hose with its clip.
I'm still in the process of installation but can foresee problems arising with the fuel lines fouling the new hose and its support as well as access to the alternator for belt tensioning.
I suppose we'll get there, having coughed up the £170, but I remain unimpressed and fully prepared to re-engineer whatever parts might demand it. I gave it a generous 3 star rating only because, fundamentally, it's a good idea.