To me this is like those multi-electrode or precious metal spark plugs. If you needed a tune up, SURE they'll make your engine run better. So would a $1.50 Champion. It's the nice sharp edge that facilitates spark production, not some cosmic shape. (As with ANY tune-up item, if you notice a difference, you waited too long to replace.)
Now, organic chemistry was many years ago, but I somehow don't recall how any metallic compound can modify a hydrocarbon without energy somehow being added to the process. So either the catalyst or the fuel must provide this energy. If the fuel provides this energy, there is less left for combustion. If the catalyst provides the energy it must erode quickly as part of a fairly powerful reaction. Either way it is probably heating the fuel (bad). There are plenty of (heavy) metals out there which have energy to give off, but due to toxicity and/or radioactivity you probably can't get them shipped in the mail. If this Fitch unit doesn't change temperature as fuel passes through it, I'm pretty sure nothing much is happening inside it. If the (conductive) metallic elements are being eroded away and carried off with the fuel, this will just give your ignition system fits.
I'd love to see an actual chemical analysis of the reaction which supposedly takes place. They say this gizmo gives you "refinery fresh" fuel. So does going to a multi-pump gas station on a busy street.