Humankind has made a habit of one-upping the creator when it can benefit in some material sense. We figured out early on that playing matchmaker to an ass and a horse produced a creature with the strength and stamina of a horse, but the nimble sure-footedness of an ass. (That would be a donkey for those of you not up on your cross-breeding techniques.) Given that as enthusiasts, we all want our cars to run like a thoroughbred and handle like, well... an ass, the notion of installing a larger engine in a lighter chassis is appealing. The same rules that apply in nature pertain to the automotive world as well: The more closely related the parent forms, the more likely they are to produce a viable hybrid. Dropping a B16A from a Japanese domestic market Civic Type R into a US-spec Civic will be a whole lot easier, cheaper and more successful than dropping an NSX engine into the same car-though this has not stopped people from trying.