Overview
K5's Mod gives her the usual increases to multipliers that come with rarity, making her already good Skill and tiles even stronger. In addition, she gains a very strong Skill 2. Her Skill 1 also grants MGs and SGs extra ammo, which makes it worth running her even with MGs.
Her Skill 2 gains different effects based on enemy tags (
for a display of enemy tags see here). If enemy Elite units are present, she buffs all allies' (regardless of position) RoF and Mov in addition to her regular buffs. If enemy High-Threat units are present, she gives all allies 100% Force Shields for 1 seconds.
As Elites are absolutely everywhere now, the first buff would be active for most harder fights, and the second effect allows the entire Echelon to ignore massive damaging attacks such as boss nukes and such if timed correctly, provided there is a High-Threat enemy present (bosses are always High-Threat).