Not that I really care to get into this new argument, but I do want to comment:
If a CR 20 treasure value should be 80,000gp, then CR 23 should be at least 140,000gp.
+1 mithral shirt of heavy fort is 37,100gp. Well under 1/3rd the total.
Mithral shirts have a 0 ACP, meaning they have no penalties for non-proficient wearers. Something I keep very much in mind when making psions, or with Twilight, arcane casters.
Mithral shirts also have +6 max dex, plenty for the 20 dex Solar.