disarm the ECU via some wiring reroute and then reworking. This leaves the thief open to arrive with a complete wiring harness and ECU to steal the car.
NICE.
BUT its still not a guarantee that your car is safe, I have seen cars stolen in Karachi via forklift/truck or even a standard truck, freewheel hub dollies etc. SO IF you really really want to protect your car, get some industrial strength cable about 3 inches thick, bury a loop of it in concrete and attach a shackle clamp to its free end and tie the car to the cable with some sort of HD lock, also get a shackle casing for the lock.
This presents 3 barriers for the thief - one to undo the case, one to undo the lock and one to undo the shackle.
The ultimate car security would be "smith and wesson" install it under the steering aimed at the crotch and arm it as such that it fires upon either security logic sequence or remote control (phone etc).