what is the best amp for B&W 802N

I'd say, do a lot of research, & probably up your budget to power N802's. And maybe start thinking Mono-blocs. Bryston 7BST or SST's might be the least expensive. And possibly Classe? But don't skimp on the power, or the quality.

I biamp with the A3CR on top and the A300CR on the bottome. This gives me plenty of power, and its easy since they have the same gain. You can pick up a used A300 for what you want to spend.

A pair of Classe CAM 350 (mono blocks) should do the job.

Over the last couple of years I've upgraded my electroncis (CD player and amp) and cables and found that my B&W 804N remarkably improved in sound with the upgrades. This indicated to me the B&W 804 are quite a refined and transparent speaker and require quality electronics and cabling to sound its best. I would think the B&W802 would be the same.

Wadia 861>>Jeff Rowland 201 mono amps>> B&W804N>>Kimber Select ICs & Kimber BiFocal XL Spk cables.

The new Delta amps from Classe are a perfect match for the B&W's. I would assume that the older ones are good too. The N802's can use as much power as you can give them, but don't skimp on the quality to get it. Best match I've heard is the CA-M400's.