Anyone listen to Zu Audio's Definition Mk3?

Vetterone, there has been a little bit of discussion on this thread re changing caps on Def4 tweeters. Charles esp. recommends Duelund CAST Cu, or Ag. What specifically did you change to, what has your experience been, and did you have the stock caps in your first pair of 4s?
This is not the most straightforward change, since one cannot practically perform an a-b, so need to go down this path with confidence that the change will be significant, and positive across a whole spectrum of music.
At the moment, what I'm loving about the 4s is a real transparency in the treble, which together with the delicacy of the FRDs is providing an almost electrostatic like quality to the sound. Can this treble quality really be improved a great deal further with cap switch?

The Def4 sub amp outputs a rated 400w into the sub-bass driver's nominal 6 ohms load. The amp is sourced from Hypex, an OEM version of the UcD400. It's as much responsible for Def4's seriously improved sub-bass performance as is the downfiring driver, over earlier Definitions.

Phil

I upgraded my 2 Mini Method amps to the new def 4 hypex versions, they are 400w as Phil says and sound far better than the old 120w ones. Bass is deeper and faster with way more headroom BUT the PEQ functions are far better allowing superior integration with the mains.

The high frequencies of the 4s are what are really impressing me at the moment. I've heard other spkrs with more "spectacular" treble, but it always in the long run seems discontinuous from the mids.
In comparison, the 4s' high end sounds so organic, and continuous with the mids. I'm sure this is a function of the new nano FRDs being so much more snappy and transparent, covering a good deal of the higher spectrum anyway, leaving the Radian supertweeter less strained and more integrated. It can't be any coincidence that there's no complicating xover to contend with.
I'm finding my Hovland amps are synergising nicely, but am still interested in hearing opinions as to whether a Duelund CAST Cu cap upgrade will enhance further sweetness in the presentation. Need more opinions please.

Zu continue to amaze. Just got back from ESCO a modded Zu 103 cart. Within SECONDS of the stylus dropping in the groove, I'm in analogue Heaven.
Sean and the guys are engineering geniuses to take the humble 103 and boost it's performance to make it work right at home with what I believe are spkrs performing right at the apex of what's possible.
Had been considering the Straingauge cart, but not so sure now, really believe synergy may be everything.