i just want to make sure if the Manual trasmission from a S13 would be compatible in a S14 since they both have the same engine
Yes.
s14 one has 4 sensor holes, s13 one has 3 sensor holes, but the trannies are interchangeable.
from what dip (derek) has told me the S14 uses a differently calibrated speed sensor, and as such requires the proper one…
However it is my understanding that the S14 speed sensor will fit in the S13 tranny housing…
correct