Of course the cars get better mileage with - whatever the thing is - installed . . . as long as the car is going downhill.

Its very easy to dismiss these type of claims as a scams, rubbish, false. But to do so off hand would be stupid until really proven wrong, which this may have already been. Obviously simple amazing solutions are discovered every day.
I think this has been covered on Mythbusters as wrong, but I'd rather have real testing done.

Is there any independent testing of this? Then again, we'll know its real if these creators end up dead.

IMHO any website that keeps scrolling down, down, down while trying to sell something, is a SCAM.

If the Hydroxy production stated at 50-70 Liters per Hour is actually true, it is VERY impressive for such a compact unit and only 15 Amps power draw. If it is true.

the web page states '... up to 5 times the gas mileage'

sure.
if i had such a device that actually worked, and patented it ; i'd be the wealthiest dude on the planet.

i have some great farmland for sale , conveniently located underneath the gulf of mexico if anyone is interested. if i put up a web site with a lot of bright colors will you buy it? hey its pretty, must be true...

Don't sell your Priuses, this looks like yet another attempt to market the water-powered car:

Water-fuelled car - Wikipedia, the free encyclopedia

However Brown's Gas is for real, you just won't be burning it in your car:

Oxyhydrogen - Wikipedia, the free encyclopedia

Breaking down the molecules of gasoline to their elemental state would reduce the amount of available energy.

A plasma is a state of matter where the electrons are dissociated from the nuclei. It requires very high temperatures, such as exist at the surface of the sun. Your engine could not contain a plasma. It would melt the metal.

Ergo, the advertisement is a scam. If any of these things worked Toyota would be putting them in all their cars.

The Poulsen Hybrid is real. It can turn gas-only cars into PHEVs. Check it out.

Except that, like the Volt, it's not actually available yet. So there's no independent testing and no way to know whether it will actually accomplish much.

Note the future tense.

Would you trust your Prius to be converted by someone who knows so little about it that he thinks it has only one electric motor?

Everyone on PriusChat knows that actually a fairly small part of the kinetic energy is recovered during regen due to the various inefficiencies and the charging rate limitations of batteries. A capacitor pack would be needed for a significant amount of the kinetic energy to be recovered.

Remember, kids, if something seems like it may be a scam, it probably is.