Move from my LS3/5A orig ownr to Harbeth which

I had the 15ohm Rodgers LS35a as ell as the esl-63s. If you are looking for similar sound but more frequency extension, the Harbeths are a very good choice.
As you already have a large speaker (esl-63) I suggest that the Harbeth 40 is the model that would make a significant difference. Sonically the 30.1 is smaller; to put it simply, a concerto for string orch will sound slightly larger with yr 63 than with the 30...

BUT, both Harbeths need amplification I don't think you have at this moment. IIRC the Paoli mono's excel in high frequency reproduction -- but they don't have much power.
Try a Mahler 2 5 or 8 on the Harbeth 40 driven by any top quality, medium powered SS amp (100+W, or ~50W class A) and you will be pleasantly surprised I think.
I suggested a good SS amp as there are many more of these around and they are usually cheaper, than tubes...

Thank you all for your thoughts, Its been many years since I've had my listening room ( had to give up to help aging parents) and now dusting off my equipment and redoing my room. The quads esl 63's, as well as the Rodgers have been very enjoyable, also have a pair of Martin Logan CLS (original. The quads developed a crackle in one speaker and was ready to take apart.. Turns out that running a dehumidifier in the room cured the problem, at least for the moment. Look foward to listening to other speakers that are musical for my classical vinyl and cd collection. Just got a Cambridge 752 and it is quite wonderful for cd's... Not very fussy but would like something as enjoyable as I have... Sometimes I switch to my D79 or D150 when I have help to move them!!

http://www.audioht.co.kr/atl/view.asp?a_id=3688

Harbeth is a weird existence. In sonic aspect it needs a tube amp. In electronic aspect it is 4ohm and low sensitivity needs a Solid state amp. Just don't buy Harbeth LOL. It is a joke at that price point.

Horn loaded bookshelves such as dc10audio Berlin II are not well designed. The bottleneck of bookshelves is the woofer, not the tweeter. With such a small horn, the tweeter can only have crossover down to around 2,000+HZ. Its drivers inside the horns are not true compression drivers for horns. That's to say, such a design loses most benefits of horns but keeps undesirable features of horns such as directivity over 10,000HZ. What DC10 did is to put an ordinary tweeter inside a pretty wooden horn of primitive design. Having such a horn-like tweeter will make the high frequency more efficient but the bottleneck of woofer does not change.