Depending on the opiate and the amount, if you normally feel .25 without the opiates then you should definitely feel the .25 while on the opiates in fact you will probably feel it stronger as opiates and benzos potetiate each other. You'd probably feel more of the sedation effect. I can tell you that when I take Xanax or etizolam with my Norco I definitely still feel the benzo but tiredness/nod factor is definitely increased. Remember though that Kpins are a ling acting benzo and at least for me have a bit of a delayed punch. Took me about 2 days of .5 twice a day (and this was when I was benzo naive) to really feel the effects.