Hi, and welcome.
My instinct - and I have nothing but a general understanding of how pickups work to back it up - is that the fu-tone thing is snake oil. Perhaps not mailiciously-marketed snake-oil, but nevertheless the product is sold as achieving a result that it is unlikely to achieve.
Magnetic pickups work thusly, in very broad terms:
The metal guitar string vibrates within a magnetic field supplied by the pickup. This vibration excites the field to the extent that it generates an electrical signal, which is in turn amplified. This signal is NOT the result of the guitar body, nor the neck, nor any other part of the guitar but the string and the pickup -- except in an attenuated way. Various neck and body and bridge and nut and tuner materials will absorb/deaden certain frequencies, which will change the way the vibrating string sounds in the pickup's field. Because the body is essentially a dead mass, i.e., as a thick hunk of solid wood that is intended not to absorb much of the string's vibrational energy, it will tend to contribute less than any other factor to how your guitar sounds. The neck, as a long slender piece of lumber, will tend to absorb more energy in various segments of the audible spectrum, and thus have a greater effect on your sound. But as long as your pickup is securely mounted on your axe, and the string's vibration is not damped by some defect in the axe, you should expect pretty much the same sonic result from guitars made of similar materials, and employing similar construction methods and similar quality hardware, and played in a similar style. The fact that the pickup is securely mounted via directly screwing into the wood, or being suspended in a pickguard or pickup ring, or being held in place with a strip of duct tape should make little if any detectable difference in the guitar's sonic characteristics.
Now here's where it seems possible that this particular mounting system MIGHT result in a change to the tone (note I don't say "improvement," because all this crap is totally subjective along the good vs. bad tone axis): The Fu-Tone system is a slab of milled metal that serves as a bracket to hold your pickup in place. A big chunk of metal placed within the pickup's magnetic field could have some effect on how it responds to the string's vibration from an electrical standpoint, as opposed to a mechanical one. I am frankly too ignorant of the underlying electronic theory to offer any more complete guesses. But to summarize, it seems unlikely to me, a half-ignorant layman, that this product will make an appreciable difference.
Leaving my half-baked understanding of electronics aside, consider this:
There are thousands upon thousands of examples of very good guitar tones (again, subjectively) coming from the same floating-pickup arrangement that's been in use since the dawn of the electric guitar era. The only way to successfully market a new guitar doodad like this is to implicitly assert that all that has gone before is insufficient - a position that is, I'm sure you'll agree, unalloyed bovine excrement.
We got to move these microwave ovens, we got to move these color TV's - into a market that is already well supplied with same.
