97 isn't overly unique, there is an extra piece in the evap systsm and a vacuum tree. Beyond that the majoirity of the differences were wiring harness and pcm. Which is only different from 98+.

Stick with your current harness, change the map connector
Get the pcm tuned for it
Swap the flex plate
Use your 99's evap setup instead of the 97's since this is what your car is already setup for.
Swap your 99 alt bracket and alt onto the motor.