I would have to say that as an older audiophile of 65 the PFR was without a doubt the best purchase I ever made ($850 on Ebay) in my audiophile life. I replaced it with an Ayre k-5xeMP and noticed a slight improvement overall, probably due to the added synergy with my Ayre amp.
I will check out SMD technology to see what they can do in terms of upgrades. Who know, I might put the Ayre back on the shelf after the upgrade.