Begin here with things you can or cannot do when programming the PCM.

DO

Always read the PCM in the car, and start your tuning with a file that you are sure matches that PCM.

DON'T

Do not copy a flash file from one PCM to another PCM unless you are sure that they ar the same GM Build.

I sent email last week on this one. GM has had over a dozen builds for the 97-00 LS1. You can't copy data from one build into another.
The table locations move in the different builds.

When you open a file in LS1-Edit, you will see the GM Segment ID's listed on the main Page.
For 97-98, there is only one segment ID, For
the 99-00 there are 8 segment ID's. These are GM build Identifiers.
If the segment ID's are the same for 2 files, then it should be safe to transfer the data from one to the other.
If the segment ID's are different, You could cause problems, or even fry the PCM, if you load
the data from one into the other.

Do not attempt to upload/flash the PCM without making sure car battery is fully charged.
Do not let other functions in the car be running at the time you are flashing memory such as radio, lights, A/C, etc.