ergi

I have never seen spark plug index on standard engine, even less with a 4 electrodes spark plugs !
and of course no anti-seize or motor oil on spark plug thread, there is already an anti-seize coating on the thread.
I never had issue to get off a spark plug with anti-seize on all my cars with aluminium cylinder head.

Petza914

That's not the problem with anti-seize - the issue is it acts like an insulator and makes grounding of the plug to the block less efficient. I've burned up a carbon distributor cap contact in very short order. Although a 997 ignition system is clearly different, the grounding issue can manifest itself differently.