If I was to pick up a spare PCM, what do I need to look for? Just match the part numbers? Do I need to have the my VIN loaded in the used PCM? I would need to flash my SCT custom tune into the used PCM. My plan would be, pick up a used PCM (w/30 day warranty), install it, flash my tune, start the truck make sure it works right, then remove it and store it until needed.