Do powercords make a difference in sound?

I would like to think I have designed a few during my career.

Dear Mr. Liguy: I would like to think a lot of things about myself (and a few of them may even be true!), but in the situation I had something of particular relevance to tell you, I'd go ahead and spell it out...

I am truly sorry but I simply do not subscribe to your accessment. I mean no offense. I am sticking to my guns that properly designed power supplies do not require fancy power cords. I do not disrespect your opinion, I simply do not hold the same opinion. I have designed power supplies for a living and fully believe that I, during my career, have designed more than a few that can allieviate the effects that would cause detriment to audio reproduction.
I mean no ill will, we simply disagree.

Liguy - Have you done any in depth listening/comparison with some good aftermarket power cords or is your "opinion" purely theory based?

Liguy: "power supplies do not require fancy power cords" Your statement maybe true for equipment to function however it does not eliminate the possibility of after market cords providing change in sound good our bad. Is this not what the original question refers to?