Alex,
Let's start with my personal mantra (often posted in the Bottlehead threads). Capacitors, wire and tubes are a matter of personal taste. Capacitors are much like spicing. Do you like habanero peppers, bell peppers or ancho peppers? We each look for different things in our playback.
The #1 thing for me is soundstage followed by clear clean highs. But the highs are where I have my hearing loss (isn't it always in the highs?). Ask PJ who worked around jet engines! We, he and I, know what loud is!
My system is in my signature, no reason to duplicate it here. My room is 24' long and 14' wide. The speakers are about 1/3 of the way into the room and my chair about 1/3 of the way from the back wall. So a rule of thirds. The speakers are well away from any wall. I use a BA sub and fill in my hearing loss with super tweeters. Software, the music I'm listening to is detailed in the posts (I think, isn't it?).
I have soldered a pair of wires on the terminals where each of the Solen caps were. Those wires come out and I attach the capacitors with the jumpers. Look at the picture in reply #10. I know what I am listening to but I'm pretty experienced at listening. I started this in the 60s. I can only report what I hear, not what anyone else hears.
Going back this is what I have said about the KK PIO:
"...they are surprisingly good sounding. Definitely better for me than the stock Solen."
"Comparing to the KK K75-24 that were playing the Solen is not as clear in the mids and highs." Not that the highs were the best, just better and more detailed than the Solen.
If I have conveyed that the KK PIO are as good as the Mundorf, that is wrong. The Mundorf caps sound the best. But the PIO are not as bad as I had assumed they would be. The stock Solen were run in for 2 or 3 weeks while I leisurely built the Eros. And have remained in there till I started this thread. So they were completely broken in, as were the KK Teflons. I think the Teflons sit at second place.
I just went from KK Teflon to KK PIO. The top end doesn't shimmer like the Teflon. The midrange is warm and present. It is kind of seductive. The bass is good but now as well delineated as with more expensive caps. But they are very "Tubey" sounding. Like I say, seductive.
Have I answered all your questions?