I would like to ask a question and I apologize in advance if this seems too uninformed or in the wrong thread... I have learned quite a bit from this conversation and have to wonder if this approach to amps is best suited to home theatre or is the appreciable sound quality also applicable to 2/2.1 channel?
In regards to these specific modules, the NCxxxMP series, there really isn't going to be any subjective sound quality difference no matter who you purchase from. Assuming they are wired correctly, the only difference vendors have is whether they offer "high end" binding posts (like WBT) or "high end" speaker wire inside the case. But, and this isn't a biased selling opinion, whether these actually matter for sound is about as subjective as the discussion of $5 interconnects vs. $500 ones.
I can say that for both my 2 channel music listening and my movie watching, the sound from these modules are perfect.
Where it gets more murky when asking your question would be NC500 or NC1200 offerings where different input buffers can be used and intentionally change the tone of the sound. But again, this isn't something that has to be considered with the NCxxxMP offerings.