What would be the best PCM to go with for a LS2-based swap/build? I'm thinking GENIII(LS1) because of tuning. Doesn't the 1998 PCM allow the temp gauge to read the actual engine temp?

 

if you can, i would run 99-02 LSx pcm. the 98s show actual temp but thats not computer related. The 98's ran a diff temp sensor in the driver side head that has 3 prongs instead of 2. the 3rd pin ran to the gauge cluster reading ACTUAL temp. 98;s are harder to tune also, or so i've been told. if your ls2 is DBW, you will need a pcm that supports it.

 

I'm running an '01 PCM, with a '98 coolant temp sensor...best of both worlds.

The '98 sensor has a 3rd pin on it which feeds a conventional temp gauge. It's not completely accurate with the 3rd gen dash gauge, but it has good precision.