Power cord length?

If I'm going to spring for an uber expensive cord-a 'final' purchase-say an MIT Oracle AC 2--is there any sonic benefit going to a 4 meter vs a std 2 meter? (I have absolutely no chance to audition). Technical details of 12 ft versus 6 ft power cord?
Get the exact length you need that will give the shortest distance to your outlet that won't interfere with your signal cables (and won't look like a temporary install - i.e. don't make it too short). If you have to cross over your signal cables, try do it at right angles or cut a piece of pipe insulation and put it around the power cable to maintain a gap between them. Done!
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make sure the length of the cord is at least the distance between the outlet and the component

After that, I don't think it matters