"This coating allowed aluminum cylinders and pistons to work directly against each other with low wear and friction. Unlike other methods, including cast iron cylinder liners, Nikasil allowed very large cylinder bores with tight tolerances and thus allowed existing engine designs to be expanded easily." from http://en.wikipedia.org/wiki/Nikasil. Just one quote. Basically, it allows them to run big bores that last longer. It is worth every penny if you are building a drag bike like a 4mill banshee.