Slightly off topic, but wanted to wrap up this thread.
The Russian FT-3 Teflon caps arrived, but I was reluctant to install them since the Mundorfs are sounding great. However, I was changing some tubes in my preamp (which I only use as a phono preamp), and noticed that a couple of power supply electrolytic caps were done (tops bulging). I also noted that the coupling caps between the first and second phono stages were 0.1uF. So, yes, I installed the FT-3 caps there (and of course, replaced all the electrolytic caps, which were already over 20 years old).
I didn't know what to expect, but the sound changed drastically. So clean and fluid. Now I'm wondering, should I have installed them in the SEX instead? Should I order another pair? Maybe this thread isn't over yet :-)