To be honest, I'm not sure that I hear enough of a difference between good $50 power cords and great $500 power cords to make the expensive ones worth the price. One thing is for sure, though, if the cord/outlet/wiring/circuit breaker can't deliver adequate current, you're going to hear serious loss of dynamics, among other things. For that reason, on a couple of components that didn't come with IEC sockets I've opened the cases and replaced the stock cords with DIY types.
I'm amused by manufacturers who tout that they use "medical grade" plugs and outlets. Read LSC 101 and related documents and you'll find that the requirements don't speak much to things that we afiles find important. One thing they do touch on, though is the force with which the contacts in the outlet "grip" the blades of the plug. This is important for current transfer.
In my own case, I use a dedicated circuit but one that preexisted and was connected to a wall switch to control two floor outlets. I checked the guage of the in-wall wiring, removed the switch and soldered the wires at that point, replaced the circuit breaker, and upgraded the outlets. Did it make a diff? Yeah, sort of. Was it worth it? Yeah, I guess cuz it didn't cost much.
I got a MUCH more dramatic improvement by installing a power conditioner. That really made a difference in clarity, upper midrange brilliance, and overall definition.
As always, YMMV. If you are of an objectivist bent, you may conclude that you don't hear much difference because there isn't much difference. To which more typical afiles will reply scathingly that you obviously have no ears.
Do want seems right and proper to you. And have fun.
Will