Hegel H590 with BW 800D

The H590 will drive those speakers without even blinking. It doubles down from 301wps @8ohms to 600, 1200, etc. The neutral nature would be a great mix with B&W’s. The Gryphon Diablo 300 will drive them nicely as well, but is significantly more $ and has an entirely different character than the 590, which I’m not sure would play particularly well with the B&W’s. Both are STELLAR amps and you cannot go wrong with either one, it would boil down to preference. Another one to consider is the H390, plenty of grunt to drive those as well. 

Thank you for the responses.  It's helpful to get some additional perspectives.

In my research, I see a lot of posts about how these speakers play very well with various mono-block setups with 600+ Watts per channel (e.g., MC601/611 or Classe CA-M600, etc.)  Which made me wonder how much I would be "leaving on the table" by using an integrated like this (with "only" 300 Watts per channel.)

I haven't had the privilege of hearing these speakers with various different amps, so have no idea how much of a difference we're talking across different amps. 

I was using a Classe 2300, which is a stereo amp providing 300 watts per

Channel  at 8 ohms, and 600 at 4 ohms.  It drove my B&W 803D3’s fine.  

What amp are you using now, and what kind of improvements are you looking for?

There's a good chance the 390 would drive those speakers without the benefit of a cable!  Enjoy!!