Wish I had put more emphasis on cables earlier

Wire.

I've been saying for years that wire is equally as important as any other component.

 
My bad. Not years. Decades.

Speakers first, wire last

Welcome to the club

Good cables can enable us to realize the potential of the entire system.

Testing in reverse, going from really good cables back to mediocre ones, with lower grade purity metals and poor shielding, while moving them around a system to compare differences can be reconfirming.

Evaluating source components and evaluating speakers with low grade cabling throughout a system can be a great loss of time and less than rewarding experience. I also place a value on cables when the rest of the system and speakers are high in quality. Low grade cables can mask the potential.  ...only as good as the weakest links.

With regards to power cords? How relevant can it be if the a.c. wire from my home fuse box to the outlet is not thick?  Would the amp be most affected by the power cord upgrade? Other than that and my dac, can't change the power cord.