I had the trim off my doors again today while messing with speaker tuning, and I got to thinking about some of the threads I had seen about guys with water in the floor because of faulty drainage, etc. As I looked into the door while I had the speaker out, I wondered what kind of seal the window and side mirrors had against rain, washes, and snow.
So I took the wife's watering can and just ran some water down the window and then looked into the speaker mounting site. I was shocked at how much water actually runs down the inside of the door. There are drain weep holes at the front and back of the doors, and the water runs out immediately, but it was surprising how much splashed down the inside elements of the door.
It is kind of amazing that speakers or electronics don't get messed up more often than they do after seeing this.
You don't even have to take the trim off to get an idea of the leakage into the inside of the door. Just take a watering can and pour some water over the window and then carefully watch the weep holes at the bottom ends of the inside of the door.
Maybe old info to a lot of guys out there, but thought I'd share.