I've been looking at the MAP-2, MAP-3, and MAP-4 cables. I'm trying to decide if/when one of these is overkill for a given application. For example, I'd put MAP-4's on my two amplifiers and on the power conditioner. But which cables would be best for a pre-amp, surround processor, DAC, digital audio player, headphone amp, bluray player, Tivo, and television? Would one be able to distinguish between a MAP-2 and MAP-3 or MAP-4 on a these sources, etc? And if so, to what extent?