Not the Salks, but I'm using a pair of NC400 to drive a pair of Eminent Technology LFT-IVs at 80db/1watt/1m.
I'm in a small-ish room of roughly 14' x 16' x 9'. And I haven't felt any need for more power, even in comparision with the amps they replaced, a pair of B&O IcePower 1000ASP amps that are rated 1000w-4ohm.
They are doing the job for me!
Greg in Mississippi
Edit: Updated speaker efficiency & room size.