"And money-back if they don't work in your system."
That would make a big difference to me to even consider an expensive tweak.
You need only resolve an issue once, like dirty power, poor matching ICs, etc. So a tweak that adds value in one system may not in another. I would drop that kind of money on anything that is not a sure bet. I might shop for it used though, then if it doesn't work out I can sell hopefully without taking a loss and another can try.
That would make a big difference to me to even consider an expensive tweak.
You need only resolve an issue once, like dirty power, poor matching ICs, etc. So a tweak that adds value in one system may not in another. I would drop that kind of money on anything that is not a sure bet. I might shop for it used though, then if it doesn't work out I can sell hopefully without taking a loss and another can try.