The Transfiguration Proteus is Cart' I have shown an interest in and once was tempted to purchase, but chose to help the Vendor the Cart' find a route to resolve the issue they had with it.
I regularly keep a check on the Market to see what turns up.
The owned SME IV sounds constrained to the Tonearm I am using at present and this also being a Tonearm I see no need to change, it is a keeper and has a couple of changes awaiting that will lift its performance further.
The SME IV is directly compared to a owned Audiomods Series V, and these are much of muchness, there is little to separate the presentation.
I have a good handle on the presentation and the perception of a constrained/excess of control during a replay.
I have regularly heard the V/12 and the OL Illustrious and can perceive the same constrained presentation.
As stated previously, if not for Rega becoming so successful as a early launched Brand and maybe not having a Watertight Protection over their Product, the Four Models referred to above will most likely not have been developed.
These are inflicted by the Geometry and Design of the Rega Adopted Methodology.
As made known as well both the IV and OL were deselected by another who was going through the motions of selecting a Tonearm.
All will successfully replay recorded music, not all from my acquired experience, are able to offer a sense of real freedom/liberty, allowing not usually revealed embedded information to form in an expansive and beyond the usual detail as the basics of the presentation. When the Envelope of note or vocal has the perception of being tangible, Tonearms of the Rega design are quite easily Superseded for a different fundamental of a design.