I had N803 paired with ARC Ref1 and X250.5 and they sounded great. Never heard the FPB200 in my system but heard it bunch of times in different systems.
There are two reasons why I’d recommend Pass -
1. Great sound with B&Ws and ARC Ref1
2. One of the industry standards when it comes to customer support and service
On the other hand with the FPB200, which was a D’Agostino design and Krell being a pretty much different company now, you might want to look into the support possibilities in case it 💩 the bed. Other than that, it’s a fantastic amp.