O'really? So only Japanese men working on an assembly line in Japan have the mad skillz to touch these engines?
You seem to be trying hard to miss the real point. It isn't about the people. They are actually largely removed from the equation here.
Much of the engine production and installation is, in fact, automated, and performed with machinery and computer controls built for the expressed purpose of their manufacture and installation in a highly controlled environment. Echoing what the previous poster said about factory paint; professional body shop personnel won't pull your leg saying they can get factory results, and neither should professional mechanics in repair shops. Not even at the dealers. Because they can't.