Regarding the beeswax cap options. . . I've had units with the standard caps, the beeswax and the copper beeswax. Honestly they're all good options. I do prefer the copper beeswax myself BUT. . . they are the real audiophile deal in that they will show you everything, in a nice way, but they can tempt you into tweaking everything, rolling everything, updating everything. . . .They can definitely take you deep into the "listening to the hardware" zone, and just as far back from "enjoying the hell out of the music" zone. . . if you're not careful. Hope that makes sense. The standard beeswax are a bit less so, very musical and enjoyable. I have only had the power supply bypass mods with the copper caps, but the bypass is a very very worthwhile investment.

As for other mods, I really like stepped attenuators myself and I think they slightly improve the sound, but that may be a moot point as only once have I made a comparison in the same component. I like them because I can keep track of where one  control is in comparison to another (especially as I have Monoblocks and dual controls on my ZBIT).

You could also inquire about glass resistors. I am unsure of their current availability or if Steve will install them in this model, but my experience with one in the CSP3 with 25th Anniversary mods I have is that they are a nice improvement.

You could also inquire about glass resistors. I am unsure of their current availability or if Steve will install them in this model, but my experience with one in the CSP3 with 25th Anniversary mods I have is that they are a nice improvement.

I am not sure of their availability either, but if you decide you want them, I would highly recommend you purchase them in advance and have Sarah pull the part while you wait for the build...which could take months.

Back late last year I made the decision in to making my next purchase the SE84UFO25.  At that time the stock was getting a bit low.  I called Sarah, prepaid her for the resistors, had her pull the parts and put my name on them.  That way when I make my purchase I know my amp will have them even if Steve is out of stock.  

These glass resistors are apparently hard to resource, and when Steve said he having difficulty, I decided to buy them ASAP.  

Hope this helps.

Dom