I started with plain romex 12 gauge - then switched to DH Labs 12 gauge stranded (from a piece of their power cable) - the improvements were quite noticeable even with the short lengths of 5-10 inches.
I use small copper spades or spring clip termination on all joints/switches, which increases the surface area of the joint which appears to provide better transient response.
I also use a bus-bar approach rather than runing the wire from outlet to outlet. (See my system for a schematic)
Net effect is that I cannot tell the difference whether the sources are plugged directly into the wall outlet or the power distribution box
I use 10 gauge Furutech into the power distribution box and 13 gauge Furutech from there to the souce components - amp is direct to the wall outlet with a 10 gauge Furutech cable
All mains connectors are silver plated copper and I use Pass and Seymour MRI outlets in the distribution box and wall outlets.
Not really an answer to your question, just another approach :-)