Differences between sources are important but tend to be smaller in magnitude than from pre, amp, and speakers. For that reason I'd upgrade the integrated first to get the qualities you're looking for and then deal with the source. A better integrated may make it easier the identify differences between sources going forward as well. I guess you could make a similar argument to do the source first, but this is the way I'd go fwiw.
By the way, if you do work on the integrated first I'd take a hard look at the Hegel H200 if it's in your budget as I think it might yield significant improvements in the precisely the areas you mentioned. The NAD is probably very good as well, but personally I want my DAC to be separate since things are changing so rapidly in that area. Hope this helps and best of luck.
By the way, if you do work on the integrated first I'd take a hard look at the Hegel H200 if it's in your budget as I think it might yield significant improvements in the precisely the areas you mentioned. The NAD is probably very good as well, but personally I want my DAC to be separate since things are changing so rapidly in that area. Hope this helps and best of luck.