Most loudspeakers contain not only junk hookup wire, but junk crossover parts. Take a look inside any given speaker and see what you find.
Danny Richie is not just some guy on the internet. He is a professional designer with many loudspeakers to his credit. He offers upgrade packages that not only replace the junk parts commonly found in loudspeakers built to a price point (almost all are) with high quality capacitors, resistors, coils, and-yes-wire, but also "fixes" the flaws he finds in the design of most speakers sent to him. That includes frequency response aberrations (often the result of sub-optimum crossover design), stored energy resonances (revealed in spectral decay---i.e. waterfall---plots) in both drivers and enclosures, any many other flaws (watch a GR Research video or two---see below).
He also sells loudspeaker kits for DIYers, which contain those same parts (as well as drivers built to his specs). And then there is the GR Research/Rythmik Audio subwoofers, designed in a collaboration between Danny and Brian Ding of Rythmik. A sealed 12" model, and a remarkable OB/Dipole sub, THE sub for use with dipole loudspeakers (whether employing electrostatic, planar-magnetic, ribbon, or dynamic drivers).