[elmin]

You can keep anything running if you are willing to put in the work. You just fix what you can, replace what you can find, and manufacture what you can't. It becomes much more tricky doing it under the auspices of an FAA airworthiness certificate though.

[sokoloff]

Most of these jets are registered as Experimental-Exhibition, which has (slightly) relaxed conformance rules vs other multi-engine turbine-powered aircraft.

Single engine turbine (or multi-engine piston) operated under Part 91 (approximately "not-for-hire") was already reasonably relaxed about "owner produced parts".