Anyone ever heard of Fuel Saver Pro? (http://www.fuelsaverpro.tv/default.asp?axel=2805). Unlike the tornado fuel saver, this one clamps on the fuel line and who knows what it does.

SnoCone,
As with any of these "snake oil" products, I'd tend to think that with all of the pressure auto manufacturers are under to increase CAFE numbers, they would jump at the bit to improve fuel economy by 27% by installing a $90 part. Since they don't, I have to assume it doesn't work.
I haven't checked to see if the FTC has slammed this company or others like it for similar products.
The best way to increase your fuel economy is to drive the speed limit, keep your vehicle in tune and to check your tire pressure regularly.
Bogatyr

What is it made from?
It is a MATCHED PAIR of tuned custom sealed Neodymium Super inductors that generate a frequency resonance between its two faces.
What makes the FUEL SAVER unique?
Operates on the principle of RESONANCE, utilizing a double chamber frequency with phased frequency modulation.
FUEL SAVER sounds too good to be true!
...

HAHAHAHAHAHAHAHAHAHAHA! What a crock!!!
It IS too good to be true. They're goddamn magnets, which do NOTHING to gasoline.

P.T. Barnum was right,
Brent

Whoa!

It has the power of the Matrix.

The only practical use for fuel magnets I can ever see is to trap stray metalic particles in a fuel filter. I've looked into the theory, and supposedly in a lab environment with glass tubing and no stray magnetic fields, you can improve fuel burn by aliging molecules and such... but put it in an engines environment and theres no way things stay aligned all the way into the cylinder...

I rely on my heat shields to do this and get terrific gas mileage. My gas molecules are perfectly aligned at all times.