I mostly do the experiment in the captura and simulacrum because lacks of stims. Stims range of effect may infinite. Refract stims is the most useful.
All stims affect all specters, summons (atlas rumbler, nekros shadow, octavia roller, nidus 'explosive insects', etc.) sadly it can't affect venari. It also affect umbra when operator is used, the effect is gone when you control umbra back.
It also affect necramech and k-drive. No noticeable change in k-drive. The refract stim doesn't work on the necramech.
Adrenal stim effect is stackable. Let's just say my necramech become the flash in captura. Don't overdose, you move too much and freezing in place.