NAD C326BEE does it need to burn/run in?

I think another lesson to be learned is that new HiFi is not always better than old HiFi just because it's newer. The technology needed to build good integrated amps matured a very long time ago (I would say the 1980s, but some might say even earlier than that), and there's really not much left to improve.  Most components in old amps can be repaired/replaced/upgraded by a competent engineer.  Electrolytic capacitors are the worst offenders for deteriorating over time, but they can be replaced, as can volume pots and switches.