Welcome to my [Daikyu] build guide.
If you're a frequent user of this bow most of these mods should be familiar to you.
I'm running corrosive over viral because I'm spending more time now on Deimos, that's all.
You may have noticed that I'm not using Amalgam Daikyu Target Acquired - there's a specific reason for that. I have this weapon tacked onto my Excal Umbra and I prefer him taking things into his own hands in specter mode, and he rarely if ever aims for the head. So that mod was useless to me. I also find that in the fast paced game that is Warframe I don't have the time nor patience to aim for each individual enemy's head, and I haven't touched on whether I hit my target or not (I'm only human).
Also you need to use Nikanas for the amalgam mod's full potential, and I'm not a fan of nikana movesets. Ergo, I avoided it. It does deal a crapton of damage though, don't discount that. You can 2-3 shot level 140 Corrupted Heavy Gunners with it, truly powerful. If that's up your alley more power to you.
Instead, I opted for [Internal Bleeding]. In my opinion, and based on my testing, it is far superior to [Hunter Munitions]. Mathematically, with the [Daikyu]'s fire rate I.B. should have a 70% chance of proccing slash on impact status proc. Fortunately, the [Daikyu] procs impact literally every single hit. It's a feature of the weapon. So, instead of a 35% chance on crit (which has an 85% chance of happening, therefore a 30% chance of proccing slash with H.M. per hit) you'll have a 70% chance of proccing slash with each hit. It's just straight up better.
For the record, I'm using [Speed Trigger] because I weirdly like the longer draw time on this bow. Makes it feel heavy hitting. [Vile Acceleration] is also viable, and it still keeps you under a x2.5 fire rate, so I.B.'s effect is still doubled. That mod was literally made for Daikyu.
3 formas are enough for this thing, imho. You really don't need Terminal Velocity or what-have-you exilus. [Vigilante Supplies] is a good choice for it's set bonus, but its effect on your average damage will be negligible.