With that kind of budget, you could look at the Odyssey Kismet or Stratos series amplifiers, the Symphonic Line integrated amps (need to push the budget a tad bit more), go higher and the Ayon Triton Stereo amp. These amps are what I carry and know well, however you will not be limited by choice in general.
The Symphonic Line especially has been known to pair well with B&W 800 series.
cheers