New power cord needed for speaker with powered subwoofer?

I am sure the manufacturer provided power cords will be sufficient. Only by trying a non-OEM cord are you going to find out. Though, to me, I think it will provide a minimal change. As long as the cable provides sufficient current to the amps in the subs, those low frequencies are going to be hard to hear a difference between cables-though I expect some may disagree.
I think you should listen to your system for a few months and then consider upgrading power cords. Only then, will you be able to discern if they do make a difference.
Bob

@OP,
Like I said, give your ears a chance to hear the system. I do not doubt that changing cables will affect sound, but you need to know what you have before you will notice what you are changing.
B

RV, you should let them settle in. These things need breaking in.
You'll be surprised at how much they can change.
Bob