The JP version of the X12 is better than stock, but no where near it's potential. The JP X12 sleeve is good, but the crankshaft is pretty plain. It has a turbo scoop and a couple of minor mods to the crankshaft, but there is absolutely no increase in timing. JP lightens the crank a little and puts a fuel ramp to fill the hole where the metal was removed. Yes, better but not best.