[Wongway]

What/where are the common leak areas, and what can we do to prevent, or preemptively fix?

I know my old X3 leaked water in the same area (driver side rear trunk area) and in that vehicle, I lost my bluetooth unit.
It's diagnosis was a clogged moonroof drain.
In that particular case, I wonder if getting compressed air blown up the tubes would've helped.

Are the E90's prone to leaking in the same/different areas?

It's readily apparent through various threads in this forum alone that people are getting their amps shorted out due to water leaks.

[tdgesq]

I asked the same question a few weeks ago, and apparently it does have to do with moon roof drains being clogged. What I never quite understood is how/where precisely does the water leak into the trunk when this happens.

[Wongway]

I could be wrong, but I'm also getting the impression either there's a potential seal with the trunk that can go bad, or something through the rear tail lights? But I could be wrong there.