if its a 98 pcm from the gtp, and your car is a 99 you could flash a 99 bin to it and make it work with some tuning changes like the tranny if you keep the na tranny.
what im saying is you have two good pcm's now 98 and 99 will swap bins with no issue.
a 97 pcm is its own animal and can only be used for a 97.
if you ever figure out what way you want to go, pm me, i can make all them changes in the pcm for ya. you just need to ship me one of the pcm's.