I've got the same switch on my Marantz SA14 SACD player. After owning the player for over a year I took the risk and moved the switch. It really opened things up especially with SACD's. If you go to AA, there are quite a few threads regarding this subject. I have experienced no damage to my Jeff Rowland Pre, Parasound Amp or Thiel Speakers.
SACD-Standard/Custom Filter
I'm sorry if this question has been asked before but I can't seem to find much information about it. Just purchased a Sony SACD and it has the above filters mentioned, the manual states that you can harm your amplifier and speakers in the custom setting. I have a Jeff Rowland Amplifier and Montana speakers. Does anyone have any experiece with these settings or is it just hype from Sony to purchase a Sony amplifier. Any help is appreciated.