Hi Scott,
I can tell you what I have found in my personal system.
The reference GC provides more resolution than the standard. It does this without adding grain or emphasis, just more information retention across the FR bandwidth. Remember, this is all back half of the wave form coherence.
I find the reference GC's the most useful on my speakers, which are very high resolution items from Plant 10 Hi Fi, and are full range single driver systems aided by EnABL. I found using the reference GC's on the amplifier too closed the lateral sound stage down to just the width of the speakers, so the Audio Prism Debut gets the standard GC set. This provides a wall to wall floor to ceiling performance, from two 4 inch drivers!
The preamp is a borrowed solid state Nikko Beta l, with the typical mid 80's transparency and refinement and hashy high frequencies. A reference and a standard RCA are paired here, since the ground scheme is common to both channels and inputs and outputs. These RCA's are on the spare output jacks. The hashiness is gone and what is left is an extremely elegant, liquid, presentation, that I had no idea could be gotten out of a solid state preamp. The phonostage is still crap however.
My Sony SACD player also has this GC combination and both the Red Book and SACD are strongly benefited, with the usual SACD slight darkness and strain having been eliminated. All of the Red Book tendency to harshness on guttural voices and most high frequency information has been transformed, back into the music values it originally came from. Even the underlying hardness to the sound has been mitigated, though not entirely.
I cannot imagine any scheme where the GC's would interfere with your Naim's grounding scheme. I have heard musings about Naim products requiring Naim cable loads to remain stable. Not sure this is true at all, but the GC has so little capacitance and so little inductance and is on the return side of the signal path in any event, that I have difficulty in imagining any damaging circumstances arising.
My system is distinctly high performance, from what are now upper mid fi components. I am quite happy with the entire package and while I was just as happy before GC came along, I couldn't stand going without. I have tried. Do note that I am the inventor of these things, so I undoubtedly have a personal slant, but I am trying to provide you with what I have found. Ozzie has a number of GC's in has system and may have a few things to say too.
Bud