Quicksilver v4 monos vs CODA Continuum No. 8 Version 1.

I have not heard the QuickSilver monos but at one time owned the CODA #8 and now own the CODA #16. For the price of the #8 I would get this instead.

Krell Duo 300 XD Like new Dealer Ad - US Audio Mart

I owned 2 of these Duo XD amps before and liked them more than the #8. They are smoother sounding than the #8. The amp that I linked above is 300 watts of iBias Class A. It sounds amazing. What that means is that the amp is not super-hot nor wasting a lot of electricity. It is not heavy either.

I think Pass Labs Class A amps transition to A/B as a protection against clipping.

Class A amps don't transition to any other class. They run at full power all the time.

Class A/B run in class A until the signal is high enough to transition to class B.

The class A to A/B transition feature is mostly just marketing.

What are the speakers you will be using?

I owned 2 of these Duo XD amps before and liked them more than the #8.

I’m pretty sure that Krell Duo 300XD is good sounding amp, but unfortunately I have some bias for vent cooling concept. Probably sounds paranoid, but the idea of some moving parts inside the amp kind a disturbing to me.