Since you have the NAD's just give them a try and see which ones sound better!
Receiver
I presently use a an HK receiver 3470, without problems. I have been told using one of my vintage NAD 7175pe or 7240pe would provide "far better sound"... , I'm using Tetra120,s and Silverline 17's. Is this technically correct given specs, equipment etc. It has been suggested the NAD's are far superior to the newer HK... I'm a novice, here to learn. Your thoughts? Thanks.