RE: can this work
The eminent Mr. Lee is incorrect, or, more likely, he was told a mistruth. Unless "assembled in the USA from Japanese parts" is made in the USA. Maybe MECOA actually DID make some parts, dunno, but don't think so.
As far as the Toki engine being made by K&B, you have to laugh a little bit! No WAY! Shuwa Industries is one of the largest engine manufacturers in the world, like I said, they "ghost write" engines for many other people, if you look closely, you will see other (mostly car and boat) engines that look an awful lot like the "K&B" 18.
And ask yourself WHY K&B would design an engine with a pull start, an 18...they already make a 21.
As far as Mr. Lee's assesment of the engine, I would say he is right on..."respectable" performance. Not "outrageous" or "hot" or "snarling" .
It also is really a buggy engine, and was designed from the start to use a tuned pipe, sticking a muffler on it and expecting it to be great is a tall order.
With the DF setup, you would not even THINK of flying without a pipe, the difference between pipe and no pipe is dramatic.