"In the medium term I'm thinking of downsizing the Cary and the two-chassis SF pre-amp to a hybrid integrated (possibly the Rogue Pharaoh) and was thinking the extra power would permit a different speaker with those last few Hz on the lower end that I've been hankering for for a while."
You should be able to take care of that with an amp upgrade. You are only going to get so much out of a 15 watt amp. Here's a list of some amps that I've heard the 2.5's on with excellent results.
Quicksilver V4, ARC VT100, Pass Aleph 0's, Rowland 10, 12, 112, Anything Ayre (Current production), Bat tube and ss. VAC 30/30
You should be able to take care of that with an amp upgrade. You are only going to get so much out of a 15 watt amp. Here's a list of some amps that I've heard the 2.5's on with excellent results.
Quicksilver V4, ARC VT100, Pass Aleph 0's, Rowland 10, 12, 112, Anything Ayre (Current production), Bat tube and ss. VAC 30/30