Noob to IAT's, picked up a GM now just splice in and go ??
 

I have a mostly BEGI kit and am running XEDE. 2002 NB

I'm getting tired of warm engine bays readings with the stock IAT and -10 temps in the winter with much cooler air after the IC giving my car bad A/R #'s.

I just got a new GM IAT and already have the port wleded on post the IC ready to install the new IAT. Do I just cut and splice the wires from the stock Mazda one? Does the stock computer and XEDE recognize the resistance output on the GM IAT properly?

yes just cut/splice.
don't know about the xede, but on all other systems you have to re-calibrate the ait values to those of a gm iat.
It doesn't just automatically read correctly.