Crimson Hunter upgrades, are any of them worth it?

As it says really. Our options are Exarch Hunter, change to Star Cannons, Night Vision and Marksman's Eye.

I don't think Star Cannons are worth it as this fighter is set up to hit flyers, night vision will only really help if it's NF turn 5 and the Markman's Eye seems expensive for a very situational usage. You should be shooting at flyers not ground units.

However, what about the Exarch? This gives you B5 which is quite nasty but is it worth the points? What do you all think?

7. Posting excessive points cost is prohibited. /Your friendly mod SS

Exarch is worth it if you have the points to spare BS5 is nice, especially with four S8 shots.

I would also splurge for the night vision if I had 5pts to spare on the exarch... just for late game night fight...

Yea, I think the BS5 really ups the reliability of the fighter.

P.S. Sorry for posting the points cost. :/

hitting on a 2+ is awesome, and I'm sure there must be some way of getting them re-rolls with psychic powers (no codex to hand).
Mind you, you can still fail that (I once rolled six ones in a handful of eight dice. Armour saves for my terminators against a guardsmen platoon as well, gutted!)
Beyond that, I don't think I'd bother, it's fast enough not to really need night vision except on really big tables.