NAD Amps - Old vs New

Has there been any significant advancements in NAD amplifiers over the past 15 years? If it comes down to just different sound and preference, then what are your thought's on older (early 90's) NAD amps vs the newer ones?

Reason I ask is because I am wondering if I should purchase a used NAD C370 and get rid of my early 90's monitor series amplifiers, with the assumption that a newer NAD amp must be better.

My current setup is:
1. NAD 3100 integrated and matching 2100 power amp (60wpc @ 8 ohms)
2. NAD C521BEE CD player
3. PSB Stratus Silver speakers (4 ohms).
4. Dayton Audio speaker cables and connects.
5. I am vertical passive biamping (one amp per biwired speaker)
NAD's have a better fit and finish now than ever before. The components they use (resistors, capacitors, switches etc.) are also getting better with every generation. The quality has actually improved since production was shifted from Taiwan to China several years ago. The older say, pre 1994 models are a bit crude but a good value used for starter sustems. Tweakers love them because they are easy to dissamble and modify etc. NAD mods bear a lot of fruit sonically because the op amps and capacitors they used in the past were horrible. The 160 or 162 preamps are excellent for the $. The matching 270 and 272 power amps are a fine bargain new and used.