Well that's a new one!! I have had water in just about every place it shouldn't be on my 123 , but it never got into my trunk lid. I'm not sure on your car but the sunroof rear drains on my 123 are out the C-pillar vents.I wonder if there is a way for it to get into the lid from the edges, the water is channeled around the trunk lip and might make its way through a rust hole or seam ??? You might try pouring water only on the trunk seal area and see if it's coming in that way ? Isn't it fun living on the rainy west coast, we don't tan ,we rust
