From measurements, bass extension is comparable, just more tubey like, but texture doesn't seem to suffer between the two amps.
Looks like the crossovers have more of an impact on bass quality than the amplificators (dynamic/variable dampening by way of variable crossover component values against fixed ones when using an electronic crossover I guess).
4Ohms & 94dB/1W/1m isn't a mismatch for monoblock Aegir from what I gather, but given the 'relaxed' bass I'm getting and the observations from trusted others that the finesse of the highs is a bit lost in monoblock mode, I won't sell my Vidar (I'm going from one to the other these days

)
Again, bass level is comparable using either amp.
The plan for me is to acquire Nelson Pass' new/future analog network crossover kit (professional PCB and matched JFET) to get rid of the shortcomings of my tentative amateur electronic crossovers ('very' palpable hum when no music played was a big hint of the limitations of my 'design'...

).
Interesting aside : I had just crossed at 800Hz between the two sections (Linkwitz-Riley 24dB/oct HPF, 12dB/oct LPF), and level matched the two amps gain/output by phone splmeter (yikes) as I had no mean of (real) measurement and I found the result sounding a bit dark.
A bit of searching and I later read about constant directivity compression driver needing a bump (6 dB/oct) from a certain frequency to achieve a 'neutral' frequency response (
link) and I guess that's what Clayton designed in his HPF as the FR with stock crossover is quite flat to 20kHz, but using a 'simple' HPF, I could clearly measure (later, once I acquired a Umik-1) that roll off and had to correct it by digital equalization (well, I was lazy as I could have implemented the linked eq) and a new level matching to restore a flat FR.
Those two (amateur electronic crossover + digital eq) might be the biggest factors in reducing top end performance in my experimentation. Hence waiting on Nelson's design, that allows for analog/electronic equalization by design and can easily be modified if needed while keeping the sonic advantages of a professionally developed product .
About slabs of concrete, I rent the apartment I'm living in, so...
