When I changed my outlets to hospital grade I could hear a difference for the better.
Initially I had zcable lighting basic powercords on everything except my electrostats. I couldn't hear any difference when I replaced the stock cords on the stats, but that left some of my electronics without an upgraded cord. When I purchased a couple VD Nite power cords for the dodd 120's and preamp, I heard a definte difference. After hearing this I replaced the stock power cords on the sl3s with the zcable lighting and behold I could even hear a difference on the stats,
With the nites on the electronics and zcable lighting on the stats the sound is more accurate. Well recorded music sounds alot better, but bad recordings sound worse.
You could try companies that allow 30 day trial or purchase 2nd hand. I purchased the nites 2nd hand.
Ray