i actually have mix/matched systems, and i can answer this question.
I used the respirator system, but was unhappy with the sound quality, as it is "too good". stormtrooper coms dont sound like perfectly amplified voice, which is what the respirator system is striving to do.
In the end, after experimentation with a few systems, i found that the respirators amp was very nice, and combined with the walmart voicechanger microphone, and stompers hovis, the sound quality is that perfect "radio" sounding voice, with great volume, and good feedback control with the volume knob from the SEA system.