I am a believer of upgraded power cords after listening with my own ears but in your case the cost may not be worth it. I would spend the money on a better amp. I think you will notice more of an improvement with a better amp and then trying a better power cord in the future.
Update power cord
I have a Rotel RB 991 power amp driving a pair of Vandersteen 2 ce speakers. t has a captured power cord now would spending a few bucks to have an IEC power outlet installed and upgrading to a reasonable cost power cord make a difference. I would like to smooth out the top end a bit.