i had bought my 94 z28 and it already had a jet pcm installed. then i went and bought a hypertech programer and installed hypertech tuning.
does one cancel each other out or do i get the best of both worlds?
also how much gain in hp does each one provide?

i think the hypertech will override the jet chip in the perameters that they overlap, however the chip will allow the perameters of the engine to remain unchanged. so the jet will keep its settings on those things the hypertech does not address. as far as power, i have heard 20hp from hypertec, and i would assume around 10 from the chip. but dont really know for certain.