Bob, I personally have not dealt with Bob but a very good friend of mine has recently. I believe he was looking to upgrade his PR-20 (with the PR-22 capsule) and my friend actually got a chance to speak directly with Bob (via phone) at fairly great length about the expectations with the upgrade etc. Needless to say, he received his mic upgrade back with a note from Bob himself outlining what he did. Talk about customer service!!
Also Bob, I'm a relative newb to this board (from a posting standpoint, but not from a viewing standpoint) and always find your insights very helpful. Specifically regarding your upgrade of your Bag End subs. I too own a pair of S-18B's and upgraded the drivers to Eminence Omega Pro-18A's and they kick.