I use a ZeroSurge on my Pass XA60 mono blocks. ASR demonstrated that signal in was no different from signal out. I take this to mean no harm, just safe power. I like safe power.
"As with all the other power tweaks, filters and cables, no fidelity improvement is to be had with 2R15W. It doesn't "clean" the AC in any way that I can measure. And as a result, real-life testing with an amplifier shows the same performance with and without. On the other hand, it is a major sigh of relief that despite pulling some 700+ watts out of the box, it had essentially no impact on the amplifier performance.
Where this leaves us is that if you like its flavor of surge protection, you can proceed to use it for that purpose and not worry about power loss.
I can't recommend the ZeroSurge 2R15W as a fidelity improvement device. As a surge protector, going by what they say it does, it seems like a better bet than many cheap solutions.