had a chance to see both the .18 and .21 brand new inside and out today-- the .18 looks beefy and like the usual 3 port engine has tons of room to modify very basic --rear exhaust version right at 100$-- for the money its worth a try.
The .21 on the other hand had more ports in the sleeve (didnt count sorry) and was modified out of the box BUT it was machine cut modifications and was not well done in my opinion, easy way to put it-- sleeve looked like crap. But for someone that wanted to break out the dremal and clean up all the port work that has been done it should be worth a try, and was priced at a little under 300$
also the sleeve's seem a little under weight as compaired to others, could just be me though.. engines both have beefy cases on them.. I wouldnt hold my breath on the box engine rpm/ HP numbers etc.. ------
not trying to cut the engine down or make it out to be some super hot engine just figure I would post what i have seen also have not seen one of these motors run--yet