The ECU is indeed there, I *believe* that I have read people just swapped over the cluster. recoded it with the right odometer, and replaced the stalk and that was it, the computer was alive! but I cant swear to this, and hopefully someone else will come along and confirm or reject it.
The ECU is I believe not too far from the wheel arch.
As for the sensors, most of the basics are there, it uses things like the fuel sender unit to identify fuel left, and the emissions to deem the efficiency to estimate you a driving range. Other warning sensors may already be installed.