N2 and air are, for all intensive purposes, the same. That is, any heat expansion air has, the N2 will have too. But what N2 doesn't have is moisture and CO2 which do vary vapor pressure greatly with temperature fluctuations a tire will be exposed to. Also, as stated, there is no O2 to contribute to corrosion (or moisture) and the lack of O2 will prevent the rubber from braking down on the inside. For the money these guys are charging for N2 though, man, thats a racquet. I work in the air seperation industry and know what it takes to generate N2.