If you are buying a costly power unit and you hope for improvement in sound, the common advice TRY before you BUY is important. Power units' effects vary by system. I have had good results with the Torus RM-20, but that doesn't mean you will like it. It is a pretty no-nonsense solution.
If it's just surge protection you are after, I second the idea of a whole-house surge protector, professionally installed.
If it's just surge protection you are after, I second the idea of a whole-house surge protector, professionally installed.