Radiation or Magnetic Progenitor. (Magnetic being the best imo)
Exilus Slot can also be [Steady Hands] (But these are already very Low recoil) But I recommend [Eject Magazine] as u will auto [Regen] a very large amount of bullets while activating Secondary Outburst.
U can swap [Lethal Torrent] for Faction mod to get 30% more dps.
U can swap [Lethal Torrent] for [Magnetic Might] or [Accelerated Isotope] & get 1 extra Primer element (& have the oposite of ur pick as ur Progenitor element)
U can swap [Lethal Torrent] for [Hornet Strike] or [Pistol Elementalist].
Swapping & losing the Fire rate I recommend Arcane Velocity or a Fire rate Frame to really make it feel juicy & make the dps really go harder than stated above.
U can also just go with Flare & Do half the dps :) Its still pretty high dps all things considered. (But dont use [Hornet Strike] together with Flare)