How does the Flashscan cable "marry" to the module it's programming (ECM/TCM)? Does it read the serial number off the module, or mark it somewhere? The reason I ask is when I buy EFI, I'd like to get a second ECM & TCM and keep my originals "untouched" by EFILive in the event I need to take the truck into the dealer for something (and to have a backup). If it just remembers the serial number, I might consider using my current ECM & TCM until I can get extras. If it marks them, I might look into getting extras before I tune with EFI.