No, I quoted this part from your post, "If few idiotic members on this list who cannot understand English want to antagonize me." Besides members of the list are actually trying to express their own view regarding "Fuel Savers", so am sure most who expressed their views here, do understand your English and are not idiots.
LOL no offence to you, I know a bass guy by the name "Yaka Bass", but I bet it isn't you
And about the topic, as majority say, Fuel savers should be not worth it (I haven't tried though). Because there many other factors which affect fuel economy which most overlook. I guess one should fix those first and see the outcome rather than "patching" other problems with "piggybacks". There are sites/forums which specialize in fuel economy related stuff. eg: http://ecomodder.com/, http://www.gassavers.org/