Hi Gvt1911,
Let I begin to say that sound is a very personal thing, before I write something about capacitors.
From my perspective, a capacitor should sound as a straight wire.... without any colouration or leaving something out. In this respect I alway use Auricaps, because they do what I want them to do.
But.... this has a lot to do with all the other components that are being used. (and I doesn't even consider the players, wiring and speakers) Say, when wirewound resistors are used, the sound is probably somewhat "cold" In that case it is a good thing to correct it and apply some Mundorf SIO's. I've tried that once, because someone told me that this would be the right thing to do.... but sadly enough the amps sounded like a jukebox in a bar... "warm and round" are the words that come up in my mind when I think back about that experience. The Mundorf I would suggest, is the Silver/Gold
type, that gives a clear, detailed and transparent sound.
But note this: all what I tell you about these caps is based on my personal interpretation of the sound coming out of my speakers.....
Peter