Possible Upgrade Advice

Try a Lyra Delos cartridge and/or maybe get the Valhalla wiring for your JMW9 tonearm.

The Valhalla wiring would be a step backwards....sure it sounds more extended in the highs (bright??) but is not nearly as musical as the Discovery.

I have heard both Discovery and Valhalla, there is no doubt the Valhalla provides more detail. Now, whether you want more detail or more musicality is up to listener, just as with all cable choices. The OP seems to be looking for more detail.

An Ortofon Cadenza Red is a nice and detailed cart for under that money, and
it's kind of between low and mid output MC range, to where your 99 w/ its
tube phono stage can probably stretch it -- I believe that tube stage has a
tube-sub option (e.g. 12AU7 => 12AT7) to raise its gain, which when
combined with the line-stage's very high 23dB gain should be sufficient for
the Cadenza. You definitely don't want to go to super-low MC (0.3mV or
lower) without a dedicated MC phono stage, though.

Another good option down the road is to upgrade to a Rogue Ares phono
(more detailed than the 99's stage for sure, and even better if/when the stock
SUT is upgraded), and then to upgrade the line-stage with an Athena (big
jump up from a 99, sonically). You could also get your 99 super-magnum'd
by Rogue (beyond the magnum status) if you don't want to go too far &
expensive on the preamp upgrades just yet.

I'd also stick with the Scoutmaster; great table if you're OK with the arm.