I seriously doubt that changing from a stock IEC outlet to a fancy IEC outlet will make a sonic difference.
!!However!! Changing a stock power cord that is built into a component by cutting it off and adding an IEC male outlet to the chassis will make a difference. I just tried this yesterday with my TV. I replaced the stock cord by cutting it close to the back panel and attaching a IEC outlet to the stub of cord left. I then used an Electra Glide cord and WOW!
!!However!! Changing a stock power cord that is built into a component by cutting it off and adding an IEC male outlet to the chassis will make a difference. I just tried this yesterday with my TV. I replaced the stock cord by cutting it close to the back panel and attaching a IEC outlet to the stub of cord left. I then used an Electra Glide cord and WOW!