I wanted to do a similar set up a while ago. I am not sure, but double check that the Pioneer has compatible output volume (volts) to match the NAD amps. I have heard of issues in the past. I spoke to Axiom audio in the past and they have mentioned the Outlaw audio amps as being strong enough to drive their speakers. I am sure the NAD's are enough, but I would review the NAD specs with Axiom to make sure.
One option, which is tempting right now is to look at the out going Yamaha RX-Z11. MSPR $5400, can be had for about $1999. on the web by authorized dealer. It should have enough power down to 4 ohm to power the Axiom, in a one piece solution. The Yamaha has the ability to add presence speakers above your mains, depending how exotic you might want to go.
Good luck. I have been thinking of trying to audition the Axiom 80's by trying to find someone near my area via their web site. I am a few months away from changing speakers. I want to hear the Axioms, the new Paradigms, or PSB.