Surge protection for amps?

I use Furman Elite 20PFi that have very tight non-sacrificial under/over voltage protection.  In addition I have whole house surge protector at the panel.

Does anyone have access to any objective measurements showing surge protectors and/or power conditioners actually degrade the sound quality? There are also different approaches used in designing these components so some may be better than others.

Here is an interesting, affordable product that you plug into one side of your open duplex AC outlet while your amp (or another type of component) is plugged into the other AC opening, for surge protection of that outlet only.
Of course, you need to use one on each of the outlets you want to protect.
Blue Circle Audio makes it.
Called The Yalu Bulala
See pictures and an explanation below:
http://www.bluecircle.com/page95.html

I have an EP whole house surge protector wired into the main panel of my house (after a surge took out one of my Vandersteen amps).....not only have I not had any problems since, but the addition, actually made the system sound a bit better.