I wouldn't worry too much about the ability of Nikisil to hold up. Many early Porsche motors used the Nikisil process, and held up for hundreds of thousands of miles. That stuff is TUFF. I have 40 yearold cylinders with a 100K miles on them that are absolutely spotless, and completely reusible without any treatment at all.
I now semi-look foreward to blowing up my motor, just to have an excuse to rebuild with a Kirkham block.
