I have the usual water in the trunk in the left compartment below the jack - replaced the rear light gaskets and the antenna grommet. I left a blanket under the trunk gasket that was bone dry while the compartment by the spare tire jack was flooded. Possibly the sun roof drain tube leaking? I haven't noticed any water in, near or around the rear seats/rear floor/ or anywhere else in the trunk except the lowest compartmeny by the jack. Any ideas? I also have water coming in at the front seat passenger's left calf - it comes in under the trim piece on the transmission tunnel. If I drive it through a car wash I get soap bubbles pouring in there. All the trim/gaskets on the outside and around the windshield looks good. Any ideas? I'm new here - but I drove my 1987 325 off the lot new in April 1988 (the last 87 model on a lot full of 88s) - it's still my daily driver that runs great and looks great. In middle school I took a mechanical shop class - all I had to do was rebuild a lawnmower engine. It never ran again and I was scarred for life, so no major teardowns are possible on this car without some adult supervision!
The only trunk leaks I've ever had in my E30 were taillight lens gaskets and trunk lid seal. If I were you, I would jump in the trunk with a flashlight and have somebody else spray water from a hose around the trunk lid to see if you see anything. As for the leak in the driver's side footwell I would bet it is the windshield seal. Mine leaked once after a windshield replacement and a good way to check for a leak is to spray some sort of foam around the windshield and then hop inside the car and blow compressed air at the back of the windshield seal (you will have to take off the lower dash panel). You will quickly see if it is leaking or not. Good luck!
