Help with bi-wirable efficient floorstanding 2.5K

That's right. With SET amps, frequency extension drops like a stone when the impedance gets much below 6-8 ohms.

What you REALLY need if you keep your current amplification is a speaker made to work well with SETs such as the Zu Druid. They claim 101dB sensitivity (and even if they exaggerate, it's still at least 96 dB which is what you need) and a 12 ohm nominal impedance. The review linked below shows the impedance never dips below 8 ohms.

The list price is beyond your stated budget but you may be able to pick up some used ones. Be on the lookout for something like this. Here's a fairly recent review.

Johnnyb53, I have been looking at that ad. The reason I was hesitating was to be able to put my other amps (SS, hybrid, tube) to use with bi-amping, and play with the possibilities of the sound. As you guys all know, most high-sensitivity speakers like those from Fritz, Tekton, Zu, Sonist, Omega, etc. are single-drivers and naturally not bi-amped.

Tvad, I will certainly pay attention to the impedence curve, rather than the single impedence figure that I have been looking at...More food for thought for me. Thank you.

If the Zu Druid is anywhere near its claimed 101 dB sensitivity, then you shouldn't need to biamp.

Cheap side - Quad 22L2s. New $1800, used $1,100 or so. Not many speakers will beat them in that price range.

I'm driving a pair with a Rogue Audio Stereo 90 in triode and they do just fine. Save your money for other things unless you're looking to spend more than $4-5k on speakers.