CNC'ing is not magic just a xerox machine for a digitized hand ported port. Depending on the original it is probably 95-98% as good, add some hand rubbing after to get another 2%. That being said unless your running an all out effort where you need every last hp, CNC'd heads from a top line porter are more than adequate and usually a little cheaper.

would be curious to see Jeff or others post flow #'s of the original hand port versus the digitized copy of the same port. Head type not important. would be willing to bet it is only 2-3 cfm.