It looks nice, seems to vibrate a lot more than a Lister though.
Two layers of board 2"-3" inches apart with coarse sand between insulates sound quite well.
As in the one video, and underground expansion chamber/silencer is almost silent, but a large car silencer in a sand box also works well.
Very interesting choice though, the most likely choice that comes to mind is a Kubota, Yanmar or chinese copy of them.
Hopefully it will be as reliable and long lived as a genuine Lister.