are all power/ground wires one and the same?

Originally Posted by SouthArk370Z

A wire is a wire is a wire. As long as your ohms/foot is low enough and the insulation is tough enough, you'll be OK. From a installer POV, stranded wire is easier to handle but, electrically, it's all the same. The connectors you use and how you install them will make a bigger difference than whether or not you are using "audiophile" wire.

Edit: The "marine" wire you mention usually has very rugged insulation. Not a bad idea for automotive use but a little overkill. The "audiophile" wiring is snake oil - any difference that they might make (extremely little in the best of circumstances) will be drowned out by road noise.