Spirit
Spirit increases Mod Power generation. It can support a priority on Weapon Mod use, whose abilities are activated in combat and powered by killing enemies according to the wiki overview.
How it works
The Traits source says Spirit increases Mod Power Generation by 1.25% per Trait Point invested, up to 25% at Level 20. The wiki overview describes Weapon Mods as active abilities and says their abilities are powered by killing enemies. The evidence does not specify a particular Mod pairing.
When it helps
Consider Spirit if your character plan relies on Weapon Mods and you want to increase Mod Power generation. The supplied sources do not establish which Mod benefits most or a best build.
The tradeoff
Spirit addresses Mod Power generation; the source lists Mod damage, duration, and casting speed as separate Trait effects.
Your next step
Review whether Weapon Mods are central to your approach, then compare Spirit with the separately listed Mod-focused Traits.
Read the supporting references
Check the edition and source version for patch-specific details. Guide methodology.