My car has been leaking, too and I finally had a chance to take a look today. Same thing, passenger side footwell gets soggy after a rain... smells all nasty
Today I took a hose and sprayed some water on the passenger window only and with the door open I could see the dripping coming from the plastic part of the door panel, in front near the footwell area.
Thanks to a dumbass window installer that tore the sh*t out of my inner door liner while replacing the pass. window, I had water leaking into the car because part of the liner was hanging into the door area, making a perfect little ramp for falling water to divert into the interior instead of out the door drain holes like it's supposed to. I took off the door panel and taped the shards of liner back to form a single piece again and closed it up. Tried the hose test and so far so good.
I'm expecting the heat to make short work of that tape in there and I'm sure I'll have to go to a junkyard and get a good door liner but at least this is keeping the rain out of the inside for now. This car is too new to be worrying about water leaking in... I get enough of that crap with my Mustang
