- Power leads will rarely (if ever) have any effect on the sound, provided they are of reasonable construction and are not inducing noise into (unshielded) interconnects. The only exceptions are those that use filters of some sort, which will reduce the noise floor in areas where interference is a problem.
Some leads are of flimsy construction, and may reduce the available power for sustained loud passages, however, the difference will rarely exceed 1dB in most cases. - Speaker cables can (and sometimes do) sound different with a given amplifier and loudspeaker combination, even where they are well designed and of reasonable gauge. Excluded are very thin or extremely silly combinations - these will always do something to the sound, rarely good.
- Interconnects might sound different, but only if they use odd construction techniques. Generally speaking, all properly (sensibly) designed and well made interconnects will sound the same - excluding noise pickup which is common with unshielded designs.
Yet again, a naysayer hijacks the question posed and it naturally degenerates into puerile diatribes. Keep off subjects raised, unless you have the faintest idea what the question is! As expected, all the silly comments come from naysayers - it comes with your ignorance