Help choosing an power amplifier

Depends on the size of your room, how loud you listen and how much power you want/need.  Given that B&W is a challenging load with a forward sound profile, a warmer amp that handles lower impedances would be ideal.

For lower power I would look at Naim, for higher power I would look at AVM.  These two brands match well with B&W, Focal, Magico, etc... where you have challenging loads in terms of impedance and need a warmer sound profile.  

I would look at a Rogue Audio Sphinx and I would roll in a set of NOS Mullard driver tubes.  This will deliver plenty of power to handle the B&Ws, the Mullards will add a bit of warmth and will deliver wonderful detail and a great listening experience.  

The stock tubes stink and this amp will be too bright for your B&Ws with them.  These would work brilliantly:

https://tubedepot.com/products/12au7-ecc82-mullard

The amp itself is either $1595 or $1695 depending on how nice of a remote you want.  

For $2K or less, this is my favorite amp and think it will outperform most, particularly with the tube upgrade.  If you haven't messed with tubes previously, it is no big deal to swap them out.  Easier than changing a lightbulb.  

I am not a Rogue dealer and have no affiliation with Rogue.  I think they make a great product.