Wouldn't upgrading the 2.4 value caps to Clarity CMR's be rewarding enough ?
If I understand @tomthiel correctly, the PUR is an upgrade of the CSA and the CMR is also upgraded. So, yeah, CMR would be very rewarding if your wallet is that thick. In early discussions with Tom, I advocated using CMR at least as bypasses. Every report I’ve read indicated better sonics from CMR compared to CSA. Getting full capacitance, however, in CMR for a Thiel XO would be wallet crushing. Tom gently steered me to CSA which is more in line with the Thiel ethos regarding performance/value. Tom had CMR that I could have auditioned as the 1% bypasses on the coax feeds but I was exhausted of comparisons by that time and I was already thrilled with the sonics from CSA bypassed with Multicaps.
So, PUR is an improved CSA at about 20% added cost. CMR is probably still better than PUR? But a 10 uF CSA 630 V is $22.13 at Parts Connexion whereas the same in CMR is $91.78. So, if PUR gets you most of CMR sonics at a fraction of the price . . .

