Thread forming is done by deforming the metal rather than cutting it.
http://www.balax.com/forming.html
Rigid tapping refers to the machine feeding the tap in and out under power feed at the appropriate feed rate equal to thread pitch. The machine keeps track of the angular positon of the tap the whole time. This keeps the threads shaped properly without the chance for gouging.
I think that this engine will do fine. I do not believe in buying the cheapest that will do the job. I'd rather have a used quality product than buy an equally priced new cheap import. Much of my own measuring equipment for my homeshop is second hand top quality.
When I go buy dumb plastic party cups at Wallyworld I make sure they are made in the US. There just is no way to justify the waste that goes into making a cup in China and shipping it by ocean freight to the US to save a few cents. One ocean freighter burns 500,000 gallons of bunker fuel one way from China to the US, then it still has to be distributed in the US.