This is a difficult question to answer since you did not post what it is you have for a stereo system. You might have some wonderful pieces, or you might have some items that could use a change. Again, difficult to answer.
IMHO, far too many people go cheap on cable. It is often difficult to look at "wire" as a piece of equipment, and it is not as "cool" as some huge amp, or a preamp with zillions of tubes sticking out of it. But something has to carry that signal from one place to another. So, it you think your gear is up to the task, then start looking at cables, especially power. I know that nothing gets a good argument going like the word(s) cable, or wire, but trust your ear and not something that someone tells you is "snake oil". There are a lot of good power cords out there and a lot of free trials. Break-in can be a bear but if you have good revealing equipment now, better power cords will really surprise you with their performance.
