20v with 40 to 80k on it which you can pick up for $600 or less.
New pistons about $500 if lucky.
20v-- sell quads $200, sell Head $150. keep the rest. As long as the valves clear the pistons who cares for an engine i drive on the street. the performance loss if any (because my current engine is old and probably not 100kw) would probably not be noticed, it is not a track car where i am trying to squeeze the last hp out of it.