Newbee,
A power cord can be any length providing the conductors and plugs are rated for the current requirements. All "unshielded" wiring is susceptible to RFI and EMI influences. Shielded PC's ONLY minimize EMI (AC hum) into close proximity high signal gain interconnect cables, which most decent IC's should eliminate themselves (ie; 100% shielded vs braided only). Keep in mind that all "exposed" Romex house wiring, from each wall outlet, is "unshielded" back to the breaker box. Now, if your house wiring is ran through grounded metal cunduit, then that's different, right? So, what sonic attributes can a short shielded "grounded" PC cable offer to footage of non-shielded cable runs? That's where all the debatable controversy begins.
I'm from the camp that's doesn't believe "Audiophile" PC's can offer any improvements over "stock" cords, EXCEPT for fully shielded scenerios as mentioned above. Exotic conductors, dielectrics, and layout construction offer nothing over the remaining non-audiophile Romex wiring, standard outlet composition, breakers, etc. If you won't believe me, than obtain the proper test equipment and have it verified. Look at each and every "Audiophile" concern at the outlet, then the output of the boutique cord(s). As long as the equipment is getting it's proper "clean" voltage supply, that's it!
Look, get a range of cables on loan (speaker, PC, IC's, etc). "Stock" and otherwise. Since you should know your system's sound at this point, have a friend perform blind testing on you. Let them deliberately fool you by periods of never exchanging "stock" cabling. If you can't pick the high dollar cable(s) every time, there's your answer. This goes for even the most hideously expensive systems. Ignore $$$ ego, and prove it to yourselves...