[thstone]

The ECU is in the trunk, mounted to the bulkhead on the drivers side behind the trunk paneling. The good news is that it is mounted vertically on the bulkhead so you'd have to partially fill your rear trunk to get water high enough to hit the ECU.

Funny that Porsche put the ECU somewhat out of the way of water in the trunk but placed the immobilizer at the lowest point in the car (under the drivers seat) where any water is sure to accumulate. Go figure.