Buying an engine from a wreck($ 4000+ -) misses the whole point about the design defects.An engine from a wrecked M96 has the same defects that got us in to this financial mess in the first place.
Raby's site has an excellent anecdote on that very subject -even he got caught with that mistake.
Broken Hearts and Blown Up Parts: Tales of a bad decision
Better to spend the $4k+ repairing and upgrading(if reasonably possible) the original engine