I have heard this model as the original design, original design undergone modification and as a Clone version built with bespoke parts.
These have not been heard in my own system but at a few Phonostage Bake Off sessions on another system and not necessarily all three in the same room on the same day.
All when heard share a similar influence on the sound being produced, which is typically a loose weighty bass end.
The Clone version being the one with the tidiest presentation in relation to the across frequency cohesion and the tightest of the bass lines being produced.
If a 834P, was in need of a overhaul or wanted to be given a change to its voicing, the variants of components selected to be used with the Clones may prove to be a interesting investigation.