On a somewhat regular basis I get emails from HBG2 fans that want information on partial kits, our engines, our parts and pieces either for sale to build a G2 at home or for use on other scratch built Gyroplanes.
I know that this is how the industry has done business over my 16 years of flying, building, kitting, redesigning, re-manufacturing, test flying and loving the Gyroplane. This is however a basket case for liability in the event of an "accident" that might involve a piece that came out of a manufacturing concern....IE: a commercial Gyroplane manufacturer, herein after CGM.
Without explaining all the ugly legal ramifications, you can simply thank the US legal system. It simply does not offer fair or balanced Tort Law in the United States toward CGM's and aircraft manufacturers in general.
Having said that, HBG2 does not sell anything but complete kits because of this litigious environment that we live in. In the long run, a program that includes a properly engineered, a properly tested and a properly supervised build is by far the best way to have a great overall Gyroplane experience.
Hope that answers the questions!