Echoes of duviri brought the new puncture and cold status effects for crit stats, and the [Hystrix Prime] really synergizes with these new buffs... Giving it an extra +5% chance of orange critting and +50% critical damage if having applied cold statuses

[Ice Storm] increases your magazine significantly, and it's even better on this version of the [Hystrix] because of the increased status chance which was a big deal on the normal [Hystrix]
[Galvanized Shot] is also good on the weapon since you will always have one guaranteed increased damage proc on hit

Viral damage is obviously the best on this weapon specially if you are against corpus with poison quill

Arcane options are up to you, but the best options are:
Cascadia flare - one of the best options you have since heat quill is one of the strongest fire modes for this gun, allowing you to deal a huge chunck of damage with it's procs
Secondary encumber - an viable option due to the guaranteed status effect that this gun brings, it wont give you a lot of corrosive procs but it can be an good late game dps dealer (note: it has noticeable weaknesses, read my encumber afuris prime build to know them)
Cascadia empowered - it doesnt synergyze well with crits, but it can bypass sentient resistances and add a new instance of damage, plus it can help the weapon stavk galvanized mods (despite cas flare already doing that)