I’d like to echo these opinions:
I wouldn’t put an $8500 cartridge on a Rega
the cartridges you are considering are not a proper match to your tonearm
Rega tonearms are not a great match with low compliance MC cartridges, and the lack of easy VTA adjustment makes it difficult to optimize the VTA, which is crucial to getting the best from your cartridge.
The Luxman EQ-500 phono preamp is a great sounding piece of equipment.
I’ve never heard the phono card, so can’t comment, but it’s basically impossible to build an add-in card which performs to the standard of a dedicated phono stage. Hence I think that auditioning some top flight phono stages is even more important than chasing a new cartridge.
Along with the EQ-500, which is superb, I’d suggest you listen to the EAR 324, Manley Steelhead, ASR Basis Exclusive High Voltage and Air Tight’s own ATE-2 + ATH-2/ATH-2 Reference step-up. Or, if money’s truly no object, Air Tight’s new ATE-3011 + step-up and the Allnic H-7000V.
I’ve not heard the last two, but the five former phono stages are the finest I’ve ever had the pleasure of listening to.
From the PC family I’ve heard the PC-1 and PC-3, but none of the others. Fabulous cartridges and one thing that’s certain is that I would never put one on a Rega, be it an arm or a turntable. These cartridges really want a high mass design and a medium/heavy or heavy arm to shine at their brightest. High mass designs are generally also low fuss designs, so that shouldn’t be an issue. Personally I heard the PCs on a Nottingham Analogue Dais with a Kuzma 4Point, which to my ears was a match made in heaven.
There’s no shortage of high mass turntables, but my two favourites are the aforementioned Nottingham Analogue and Acoustic Solid. Obvious medium>heavy tonearms to partner them with for use with a PC-1 might be the Kuzma 4Point, Origin Live Enterprise or Agile, Helius Phaedra, Thomas Schick or the Dynavector DV-507 MkII.
Anyway, that’s my 7 or so ¢. All in my subjective opinion of course.