Lon, I'll admit that it was a tough decision once hearing the Sarah at Steve's place. My order was in for the SE84UFO25 prior to the 2023 Decfest. The Sarah was introduced at that time. It is one sweet gutsy amp without that syrupy 300b thickness. I left telling Sarah my plans of changing the order. Over time(3 years and 2 months) I stayed with the original order. Why? I wanted a transparent boost from the source. I'm happy so far with the decision as your are with yours

I think my want for an additional input with plans to upgrade the CSP2+ has been solved. Your old ZP3 with Steve's added tape mod has so many plugged holes in it that could facilitate the necessary switches and RCAs.
Kahana Jack, I totally agree with a 25th paring. Don't want to go with the wait again. For me the two white tops with a 25th on the bottom works well. The trio can get me in audio bliss in short order. The black base CSP2+ is actually painted walnut and upgrading it to a 25th should take a matter of weeks.