OK.... science.... or should I say scientific theory that is totally unproveable without many thousands of pounds of lab tests...
It makes scientific sense that if a combustible is polarised it will burn brighter/more efficiently. Aids in spread of chain reaction etc...
in practice this is a load of bull.
one magnet on one side of a fuel line will make absolutely no difference. I'd be very dubious if it made any difference to a matiz, and just adding one tiny magnet to a 2.0 litre plus will most definately do nothing.
if the fuel stands any chance of being polarised it needs to pass through an magnetic field, not past one. therefore you would need at least 2 powerful magnets, one on each side of the line.
it is theoretically possible on the omegas, the v6 at least, as the fuel goes through a nice circular metal tube right at the side of the engine. if you were to stick several VERY POWERFUL magnets (would have to be rare-earth ones, not factory produced) to these metal pipes that is the only chance you could possibly get of polarising the fuel.
that being said I find it very very hard to beleive that you could possibly get enough magnetism to acheive any noticeable results in such a small confined space.
I have tried this, I pulled the magnets out of 2 old dead Hard Disk Drives. two massive rare earth magnets on either side of both fuel lines.
Now the proof of the pudding is of course in the eating... my fuel consumption has gone from 26 mpg over a tank to almost 28. I am more inclined however to put this down to psychology. I know I am taking measures to try to improve fuel economy which I think is subconsciously making me drive slower.
The only thing I can suggest is that you try sticking the most powerful magnets you have, if you have any (old dead hard disks are your best bet), all around the fuel lines as close to the engine as you can. then see for yourself if you think it helps, psychologically or otherwise.
Don't go and buy any magnets! its a stupid waste of money!