Are manufacturer AC cables good enough?

I have two PS Audio AC3 and two Pangea AC 14 cables I don't use.  My thinking is that Ayre wouldn't supply cables that are inadequate for their components.  Is that thinking flawed?

Ag insider logo xs@2xdbphd

You had a contradiction, your intellect said wire is wire should sound the same.
Your experience said no the wires sound different, better.
When humans have dissonances they try to resolve them it’s just what we do. You solved yours by deciding to "just to ignore the science, for the most part, and the debates, and simply enjoy the music." If it worked then your dissonance has been resolved.

It's interesting because I did something similar. Instead of ignoring science I used science and discovered I didn't really hear differences in cables or dacs it was my human frailty or a human fault or perhaps a survival mechanism that evolved. Anyway it's just who we are you solved your contradiction one way and I another.
You need  to "lift" (disconnect) the ground at the EQUIPMENT end of the stock cord ... cut off the IEC plug at the equipment end of the cord and install a new IEC plug with only the hot (black) and neutral (white) conductors connected ... The ground conductor (green) should be cut a little short of the new IEC plug and not connected.  You have just turned a stock power cord into a respectable audiophile power cord ...
Very bad advice. You have just created a safety hazard. Disconnecting safety grounds is not the remedy for things such as ground loops or AC noise.
@ cleeds, turnbowm 

No, disconnecting the ground conductor at the EQUIPMENT end, as I specified, does NOT create a safety hazard.  However, disconnecting the ground conductor at the wall outlet end does indeed create a safety hazard!  A bit of research into equipment grounding techniques will explain why.

Some audio equipment now comes with a workaround for the UL power cord grounding requirements:  you may have noticed a "ground lift" switch on the rear of the chassis. Toggling the switch to the "lift" position accomplishes the same thing as disconnecting the green ground conductor at the equipment end of the OEM power cord. 
My new Anthem STR came with a two blade plug and two blade IEC connector on the amp. It has the CE, RoHS,FCC , cTUVus, certifications on it. In case you don't know the cTUVus is a direct replacement of UL and CSA marks.

Why would one disconnect grounding? Wasn't it placed there for some safety reason?

My amplifier and CD player (same brand) came with two-pronged cord and connector on the devices. I am not sure what certifications they have, but they are from a relatively reputable manufacturer. I somehow doubt they cut corners there. My music server, from different but still well-known manufacturer, has three-pronged connection.