For all of the following, I am presupposing a named YT-1300 + Gunner, alongside 2-3 ships flanking, being the standard Han Shoots First fleet archetype in standard 100 point fleets.

Adrenaline Rush: With a 360* firing arc, the YT-1300 does not typically need to perform red maneuvers, so this winds up being fairly irrelevant.

Opportunist: It would seem nightmarishly potent for HSF fleets, but it will only add the bonus die to one of the two attacks. Still fairly decent, as it doesn't require an action to gain the bonus die, but probably overcosted here.

Intelligence Agent: Given that you'll be moving last to shoot first, this seems practically worthless. However, you'll typically have two other screening pilots flying alongside you, and this can aid them into a superior position...if they have Boost or Barrel Roll. If you use Chewbacca instead of Han, you can have 3 Prototype Pilots as your screeners at 99 points, making this viable.

Saboteur: A 50/50 shot at extra crippling at Range 1. Potentially a finisher while you shoot at a healthier ship. The best way to combat HSF is to have a swarm at Range 1, and this aids against that offense.

Recon Specialist: A potential replacement for Marksmanship in function. You're sacrificing Crit Potential for Defense potential, and trading the Elite Pilot Talent slot for a Crewman slot. Since HSF usually flies the Chewbacca Co-Pilot as a defensive crewman, you'd need to focus-block two crits to be a straight improvement, and you have your Elite Pilot Talent slot open to aid with that endeavor. Definitely worth checking out!

Flight Instructor: The Falcon needs extra defense. This technically qualifies. If you're going to spend 4 points on a defensive co-pilot, go with Chewbacca every time, unless you feel you can dodge better than two Crits with this thing.

Anti-Pursuit Lasers: Given that you'll typically have a higher pilot skill than your opponents (thus the 'Shoots First' part of the title), they'd have to be fairly poor players to ever give you the opportunity to use these.

Hull Upgrade: Extra HP at slightly cheaper than a Shield Upgrade, which is only superior against Crits. Given your low evasion, quite a lot of regular damage will get through, so this is probably better.

Do you think any of these stack well with pre-existing upgrades? Have I missed anything?

Recon specialist looks like a good upgrade over marksmanship. You lose the crit but have a chance at being able to use a focus defensively. It would be best used with Gunner, which sadly means that you can't take Chewie.

I would consider this at 100 points:

Han + Recon Specialist + Gunner (54)

Blue + Advanced Sensors (25)

Rookie (21)

Han dies faster in this list without Chewie, but the Blue should put out more damage than a Rookie, and might pull some fire away from Han.

Another idea is

Han + Falcon + PtL + Recon Specialist + Gunner (58)

Rookie (21) x2

Han + Marksmanship + Chewie + Gunner (58)

Rookie (21) x2

I agree with the above poster. I would think PTL+MF+Recon would be superior to Marks+Chewy. The point value is the same so that's not an issue. I've never seen a YT go down in one turn, which means that if you F+E every turn, you should come out at least equal (though they may not be cancelled crits) as far as overall health. In addition, there is the potential for you to not spend both focuses on attack (say, in the case where gunner doesn't kick in... or the chance that you roll all hits/blanks), and you'd be left with at least 1 focus to use on defense in addition to your evade token. It would also be useful against opportunist.

Since the traditional Han takes marksmanship, if faced against a pilot with opportunist, one would have to decide whether to take the focus (and not use it on attack) to prevent the extra die from being rolled, or buff Han's attack with marksmanship. If you did the PTL+MF+Recon combo, you would just have to not spend that evade token until the opportunist shot at you (which should be a fairly high PS anyways since it's an EPT.

recon spec is good. Means that instead of marksmanship, your Han's EPT slot is now free to put other things, like Veteran Instincts, expert handling, determination etcetc

flight instructor is a good replacement for chewbacca crew.

intelligence agent + navigator is good to help you chase targets / avoid collisions and hence losing actions, but without gunner and other supporting crew upgrades, i highly doubt Han would find this a good choice.

Oh right, do watch out for Jonus + 3 TIEbombers, those things can end you immediately. Let's put it this way, 3 cluster missiles + jonus own attack yields a maximum possible damage of 20 on a single target, namely your falcon. On a normal day, you are looking at say 1 hit from jonus' own attack and around 4-5 hits per cluster, netting you a rough 13-16 damage on your falcon on the very first combat round. Meaning, your Falcon + chewbacca crew is very likely to kick the bucket immediately, or survive with like, what, 4 hp left after using chewbacca crew

I personally love recon spec. I usually run it on the firespray where it is godly, but I could see it being amazing on the falcon also.

Oh right, do watch out for Jonus + 3 TIEbombers, those things can end you immediately. Let's put it this way, 3 cluster missiles + jonus own attack yields a maximum possible damage of 20 on a single target, namely your falcon. On a normal day, you are looking at say 1 hit from jonus' own attack and around 4-5 hits per cluster, netting you a rough 13-16 damage on your falcon on the very first combat round. Meaning, your Falcon + chewbacca crew is very likely to kick the bucket immediately, or survive with like, what, 4 hp left after using chewbacca crew

So finally the HSF is going to be a HDF (Han Dies First) list? ^^

Its just a matter of timing ... use your escords to prevent Han from getting shot in the first round.