I used to own the B&W 802 D2 for a few years. I powered them with just a Denon AVR-3312 receiver just fine.
So I may not have owned a B&W CM series, but I know the B&W 802 Diamond series can be EASILY driven by a single Denon 3000-series AVR.
I'm pretty certain if you ask any B&W dealer, they will say you need a Classe 300WPC amp.
I can understand you wanting/desiring an integrated amp or pre-pro + amp.
Like many other members here, I've owned quite a few components over the years. So I understand the appeal.
If you desire an Integrated Amp, I think PENG's suggestion of the Anthem is absolutely solid. It certainly has enough power to drive just about any speaker in the world.
I think Pre-pro + Amp similar to an Anthem BRAND NAME may cost a lot more.
I can absolutely understand if you don't want something like an Emotiva.
I think Outlaw also makes pre-pro + amp. But you may not like Outlaw either.
As for "minimum impedance", I agree with PENG. It is misleading.
I used to own towers that have minimum impedance of 2.7 ohms. Actually all 5 speakers in my 5.1 setup had minimum impedance in the range of 2.7-3.5 ohms. Yet, I powered all 5 speakers with just a single 50WPC AVR to very LOUD volume.
The salient information from the spec is the NOMINAL impedance (not minimum impedance) and the recommend power. So if your speakers are rated for 50-200W, then anything between 50-200W is fine.
I think the salient thing is that the amp (or AVR or integrated) can handle 4 ohms with ease. For example, a Denon 3000 series AVR can easily handle 4 ohms load, but a comparable Yamaha AVR cannot handle 4 ohms load with ease and may go into protection mode.
I used to also own the Revel Salon2, which I have used an ATI 60WPC amp to power just fine.
So again, the salient thing is QUALITY (ability to handle lower impedance).