Agree with everything Moodles says, but would add;
They do tend to leak, and its not much work, I'd probably do this.
I'm guessing this is the idler and/or tensioner stud. You'll be replacing the idler and tensioner when you do the belt. Some have had their studs snap, but i'm guessing those studs may have been mistreated in some way, eg. overtightened. Probably wouldnt worry about replacing the stud.
CRD used iridiums on my 300kw engine with their tune. No problems, lasted well.
600 is 315 celsius. Nulon Xtreme performance is rated to 280 celsius, and far cheaper. Been ok for me at track days.