I have used the Denso wires, have not had any issues with them.
I know they are cheap on Rockauto, and you might be worried about them, but they work fine on my P5. I also use the long reach plugs, NGK V Power ZFR5F - 11, and I noticed a slight difference for the better when I was using the US motor.
I did have an issue a while back with the NGK wires, the boot that connects the cylinder 1 and 3 wires to the coils did not have a tight seal. I verified the part number on the box, but maybe the wires were misplaced in the wrong box somehow.
They made me nervous, so I put the old ones back on, returned the NGK's to Advance Auto Parts, and bought the Denso's off of RockAuto. I have purchased two other sets since.