spica and ls3/5a's

No.

I have owned spica angelus and tried Ls3/5s for an extended weekend demo and the imaging of the ls3/5 is nowhere near that of the spicas.

I couldn't believe it at first given that the ls3/5s are considerably more expensive, but after 2-3 days when the spicas were replaced the pinpoint imaging (totally absent on the ls3/5s) returned.

I eventually changed my spica angelus to Green Mountain Audio Europas because the spicas were too difficult to move. The Europas are slightly more forward than the spicas but better in all respects, including imaging.

Comparing Green Mountain Europas and LS3/5s it's not even close. The LS3/5 is a nice speaker ... unoffensive, but it is an ancient design. The only way in which the LS3/5 could be preferred is that it is less revealing of upstream equipment, and produces more of a "romantic" sound than the Europas.

Phil,
The LS3/5 might beat the Spica on tonal accuracy ... I'll admit that. But the margin of victory would be quite small IMO.

On the other hand when it comes to imaging and casting a wide deep soundstage there is no competition. The LS3/5 is not even close to the Spica. It is this that makes the Spica such a legendary speaker.

As to the issue of impedance I would think it would depend on the amplifier, its rail voltages and its ability to deliver current and double its power into 4ohms. Some amps can't deliver current (older Quads) and sound much better into high impedances. Others (Cyrus, Densen to name a couple) deliver current in spades and seem much less fussy about impedance.