Idk about power gains, but having a dampner that can FULLY cancel out cross torsional stress in the crankshaft is a big deal, i imagine it would allow the internal components to spin "better"
Think of an improperly balanced tire, like a low pro tire on a big wheel, throws the feel of the whole car off, but a perfectly balanced tire and wheel allow the vehicle suspension and steering to work to their perfect potential, so to speak
That is how i interpret the ati and fluiddampner literature at least....