Robert M Watson Jr
I wonder if they will perform this process on an existing used piece and how much weight it will add and at what price?
I can't speak for Brad on this question, but you have nothing to lose by contacting him through the Kingfisher website and asking.
I believe that the process increases the weight of the bokken by about 30 percent.
There are some interesting videos by a fellow who smashes various bokken (including a Kingfisher grade 7 hickory, NOT enhanced) into a tree in his yard. You can see the results at http://www.youtube.com/watch?v=ceQPBmSc_x0