If you have no "dirty main problem" you wouldn't need any of them! Save your cash and spend it on something that make day and night improvment is a better bet. However, if you really have a need for main cleaning gears then buy a main filter block as you wouldn't need to buy those fancy power cables (if the Main is clean by filter, the power cables are, surely, would be waste of money unless you want to look like an audiocool)