Heres the door shell pic I was gonna put up yesterday. Study hard. On this design, the weather liner seal is critical for keeping water out. Any spots on the bottom front quarter of the butyl bead that are not stuck to the door let water flow right in. It drips from behind the trim panel and drip by drip it goes over (or under) the sill trim.
If it goes over it, there won't be a trail of water, just drips that go straight over the sill and onto top of carpet. If its going under the sill trim you simply can't see it but it goes directly onto wiring and carpet pad sponge. Its just a possibility but a common one. Incoming water from a weatherstrip leak would be coming in up by the kick panel, but this leak ends up below or behind the speaker. See the water marks in pic. There is a deflector of white plastic above the speaker, it deflects water coming in at the belt molding / mirror / front of glass area away from the liner. If that isn't there plus the butyl has a gap, thats a bad leak.
