The phono stage is excellent. I was able to compare it directly it to two "Class A" phono stages and preferred the Cary. I had both the MC and MM versions, paired with the V12R amplifier. Both were very quiet, with background noise practically indistinguishable from the linestage. The MC version worked well with my Benz Micro Reference .34mV cartridge, with plenty of gain to spare. In my experience, the sound was on the warm side with very nice, full sounding tonality. Part of the sound could have been because of my amplifier, but I was also able to distinguish differences between the other two phono stages that I had on hand. Bottom line, (in my opinion) installing the phono stage into your SLP98 is definitely worth a try if the upgrade cost is as reasonable as you say it is. As a bonus, it might help the re-sale cost of your preamp if you ever decide to sell it.