Unfortunately I've had a catastrophic engine failure on one of my Mazda 6s and I'm rebuilding the engine in the other chassis, the one that was originally meant to be for spare parts. I'm wondering what would be an easier option. To swap the ECU and potentially the ignition as well, or just have the software (unused, but activated) moved to the other VIN as the original car is going to be scrapped. Please enlighten me. Thank you!