If clamping a couple of magnets around the fuel lines could SOMEHOW, and it entirely defies science that it even MIGHT, but if it COULD........ give ALL those improvements claimed..... with EVERY single manufacturer spending GAZILLIONS trying to meet ever tougher emmission controls, offer better ecconomy figures and not loose performance...... Dont you think something so CHEAP wopuld be fitted as standard to every ruddy car sold, as standard?
Its UTTER balonie! briefly, as the fuel passes between the magnet, SOMe fuel molecules might gett mildly realigned by the magnetic flux..... but as soon as they are out of the flux, then the ionic forces between them will put them into pretty much the same ofer they were in before. And even if they stayed slighly better straightened.... wouldn't do much..... the fuel will get sucked and squashed up to the point of entry into teh charge, where it will either get sucked through a tiny orafice, which will do more to 'polarise' the molecules than a magnet would, or squeezed, likewise through an injector nozzle.... where the molecules will be released into free air, and have the natural tendancy to sink.... exept that air will either be in the inlet ports being wisked up by the turbulance of the corners in teh pipe work, and the stop start of the air column being dragged down different corridors of the manifiolds, until it all hits the combustion chamber..... which in molecular tems is a million miles from where the magnets were...... and THEN the molecules are going to get churned up as they are squashed on the compression stroke, before something sets them on fire........ where, the ionic forces involved in the breaking and making of the molecular forces are HUGE in relation to any residual magnetic polarisation these poor hydro-carbons might have retained from passing between a couple of magnets......
You might as well get a Bhudist priest to pray over your petrol tank when you fill up, for all teh good these things are likely to do!