Nothing wrong with the standard extractor that Remington fits - its a £15 part that is a five minute task to change IF it ever goes wrong.
I change them as a matter of course if I'm doing a rebarrel (for a new one)
I have one rifle (Rem 700) that has a Sako extractor - I wish id not bothered - brass hitting the windage turret every time i extract - waste of money.
Does it weaken the bolt head,,,, it does nothing to weaken the lugs, which is what matters.
Most custom remington "clone" actions fit a Sako style ejector of some sort so I doubt there is any issues - though none I know of send brass into the windage turret like mine does - mine was done a long time ago by the a reputable gunsmith.