After posting my original comment in this thread, I read through the rest of his product description, and I have to admit that it left me a bit nonplussed. I agree with Dave when he said that the benefit the device might accrue to a single amplifier is dependent upon that amp's having a marginal power supply, but even then, it sounds like voodoo (and the increase quoted is ridiculous). Put simply, the imply is that if both channels are pushing at the same time, the drain on the power supply will be greater than if one pushes while the other pulls – I wasn't aware than pulling was 'free' (actually, it sounds as though pulling is more than free; it's using negative energy - sounds like balancing the matter/anti-matter consumption of the warp drive

).
Regarding your general question about having too much power - worry not. Then again, I seriously doubt one needs more than 400wpc to drive a pair of 1.7s.