Will a quality USB cable make a difference....

For what it's worth, I was unable to hear any difference between the the stock USB and one made one of the "name" cable companies that cost $130 retail and I can certainly hear and appreciate the difference between brands and types of Interconnects and speaker wires.

I've spent a small fortune on interconnects and speaker wires and do think I appreciate good cables. I agree on the DAC comment as well. I didn't try the Wire World product but did try Cardas, Kimber and Audioquest and could not hear any difference between those and what came with my Mac.

Just my two cents. I can think of a dozen better (more Pareto optimal) uses for the money just in terms of tweaks and the like.