Good as the newer 4 port 231/260 PU/H/M engines are, sadly sense introduction KZ has done little too nothing in maintaining this forward into the future philosophy
Now 2 years after the fact of RCMK outright copying the basic platform taking the engine design and making it more refined and purpose built as a marine power house ... Zenoah has not even blinked or done squat ?
Either those now owning the model faction of KZ ( Husqvarna ) have no interest in further R&D within the R/C model markets and are simply milking sales by just sticking with what proven until sales drop enough making it no longer profitable ?
Or more likely knowing what has been talked about for YEARS now is 2 cycles as we know them are soon to be obsolete in this ever increasingly clean air and pollution free world ?
RCMK may very well just be capitalizing on this "so long as it legal to market and promote small displacement 2 strokes" that we will see this evolution.
Honestly tho if we watch and learn by what we see, truly global manufacturing of small displacement internal combustion engines have for the most part abandoned 2 strokes