I'm going to go against what most people have stated here on the thread but. In my years of listening to systems and changing cables I have found the preamp to amp interconnect is the most important and most apt to changing the sound of a system when upgrading. Simple reason being that you're volume (or in this case the electrical power) is lower than the one the source components use normally. Usually about by half. Because we never listen to our systems at full volume. The source components almost always see full power during a song.
So to make a long story short reserve your best interconnect for the preamp to amp connection which usually needs a much lower noise floor and better resolution for those lower volume levels.
So to make a long story short reserve your best interconnect for the preamp to amp connection which usually needs a much lower noise floor and better resolution for those lower volume levels.