Not sure that I get it??? I work for an atmospheric gas company (med, lab, and welding gases). Nitrogen does work well as a cleaner when used cryogenically as a liquid. I'm not sure that a non-flamible gas such as nitrogen (liquid or gaseous) could really be of any benefit when mixed with fuel. I'm not saying it does'nt do what they say, I'm just not sure I believe it.
To me, it sounds like the next best "foo foo" gas that someone is comming out with. The welding gas companies are notorious for this. You can only go so far before you start creating more problems.