Dunno about the power cables, but in my experience with HFC signal cables, they don't seem to follow the same pattern as that of other cables in that a lower level cable will act as a "bottleneck." By that I mean that adding a higher level cable to replace a lower level cable in a full loom of lower level cables will have minimal effect until you upgrade all of the lower level cables. Kind of like adding a freeway lane that merely moves the bottleneck elsewhere and does little to alleviate traffic. Conversely, I have found that HFC cables are additive--the more magnets the better and there doesn't seem to be the traditional bottleneck. So if you have all regular CT-1s and add a UR cable, it would likely have more effect than upgrading all CT-1's to E's, since the effect seems to accelerate more the further one goes up the HFC line.
Maybe others here can weigh in but this has been my upgrade experience. I posted more details on my experience with HFC cables in an earlier post above. IMO, the lower level of signal, the more magnets seem to influence the sound.
