As far as I understood, problems with the ECU soaking is more a matter of time (blocked drain, dripping roof, leaky doors / simply spilling a bottle of water).
So I figured... why not wrap it in plastic and seal with silicone as a preventive treatment, so when the problem arrives, you'll have "one extra life" left while you're dealing with the water on the carpet?
P.S. My key fob not working and the alarm being silent (THANK GOD FOR THAT...) could be a sign of ECU damage somewhere in its previous life? I have no error lights on the dashboard, and the car generally runs exceptionally well.