A) The p500 brakes like to get Tennessee mud in them and squeel.
It's a TN mud thing I think, doesn't happen with Ohio mud.
Once a year (in preparation for the Takeover) I pull the pads and clean the calipers, grease the pins and put it all back together.
The squeeling drives me crazy, you would think honda could do better.
B) l would stick with the stock pads.
But then, I would.
They change the pad material formulation every now and then.
Look at the part number for the current p520 (i didn't bother to look up the latest).
But I'm still on the original pads for my 2018 p500, benefit of engine braking.