Upgrading power cables

Recently auditioned some power cables in an A-B test and became a believer in the benefits of a quality power cable. Since the test was only done with an amp. I wonder if it is necessary to upgrade the power cables of all my components (solid state amp, tube preamp, SACD player). If so, should all components have the same model of power cable? What should be the first component to upgrade?

Thanks for the help.