+++1 for the CODA S5.5, though I don't know how it would pair with the Harbeths. I would reach out to Doug Dale founder and CEO of CODA, he is really a great person to talk to....I spoke with him twice before buying the S5.5 and once afterwards. 45 pounds, full class A, reserve power for days.
I've only had mine for less than a week, but it is already producing magic. I have it connected to my Buchardt Audio S400 MKIIs right now (87 db 4 Ohms) and the CODA is owning those speakers. Also had it connected to a pair of Clayton Shaw Caladans, but they were really easy to drive at 93 db.
There is a thread right now started by Jonah5 who is reviewer Terry London, who has one in house for a review. He thought so much of it that he posted an early "heads up" post here on Audiogon......check that thread out.