The new wounding code applies "wound points" to the target. The text you see for wound status is related to the number of wound points the character has. Just like you see text descriptions for region morale that depend on the actual morale percentage of the region.
There is no such thing as a "perfect attack" for an infil that generates a special kind of wound. Some hits do more than others. But there is nothing special about an infil attack that can generate a special kind of wound.
As for the "invisibility" code, it could probably be pulled out of the SVN repository if needed.
