IMHO, I would replace the main power cord to the system first. Install at least one, preferably two, dedicated lines from the breaker box to upgraded outlets at the system. It is better to use upgraded component power cords with dedicated lines than daisy chained AC wiring to a $0.97 wall outlet.
Power cord replacement suggestions
If i were to delve into the fanatic behavior of replacing power cords, is there some concensus on where the most impact would be gained, whether on source, pre, or amp, or is it just different for every system and need to experiment. Thanks for any advice.