System i built over the years on a budget. Love the sound that comes from the Zu druid. All the interconnects are DYI made from VH audio recipes. Haven't upgraded in a while since i haven't seen a need to. The only thing i find annoying is not having a remote for the integrated amp. 18 watts from the Dared amp is plenty enough to drive the Zu speakers to high volume without any compression. I use to have high powered solid state amps with low efficiency speakers. Those have moved down to my home theater room consisting of Nohr Marble 9 speakers matched with Emotiva Amp and preamp.
You say that the ZU sensitivity more than made up for the loss of power going from 845 to 45 ??? Im using a Cary 805 and Omega 6" hemp which is already pretty sensitive. Wondering what a 300b would do?