I have the C356 and it is not in service. My recommendation with your budget is to buy a rogue audio cronus magnum ii and some KEF LS50s.
this combination will sound far better than any speakers (e.g. Harbeth C7ES) you could ever add to the NAD.
this combination will sound far better than any speakers (e.g. Harbeth C7ES) you could ever add to the NAD.