I see these from time to time, but not often. I remember reading about them at the time and boiling the long story down to: it’s a 3 stroke with no compression stroke, requiring the forced induction to fill the cylinders. It trades off the parasitic loss of a supercharger for the thermal efficiency of not having to do it’s own compression and somehow comes out ahead because Japan is magic.

That kind of sums up my understanding of these engines, that and by common logic this set up would probably be easier on the rings/bearings etc. Any Mazda guys or girls care to elaborate?