Kubota side doors cost between 3 and 4 thousand dollars which is out of reach for me. I put this together from stuff laying around. Works better than I thought with a golf cart heater. It stops the air flow enough to hold some heat.
It was more of an experiment to test the concept. An American company called 'Green Mountain" makes a set of zipper side doors in the 400 dollar range that I am considering. I know they would look better...LOL..
When it is -20 out, 2 feet of dry, blowing snow and the wind is howling about your Kubota, looks are the last thing you will be thinking about. At that moment, I would take a door made out of kotex pads stapled to a piece of half rotted cardboard (preferably clean kotex, I do have my minimum standards) if it kept the blowing wind out and kept a bit of warm air in.