I have a significant amount of water coming in the passenger door - didn't realise quite how much until removing the mat to find I could wring it out
Not 100% sure what the problem is, though I did find when doing the sound deadening mod that both the door membranes had previously been butchered (see earlier in this thread) presumably when window regulators were replaced by previous owners which I see in the service history; rather than peel down the membranes and do the job properly they were simply cut through the middle and not re-sealed. I didn't realise how vital these 2 membranes are to keeping a water tight car until investigating my leak!
Could be a number of issues however from reading around: the membranes, the front drain channels being blocked, the rubber seal which meets the window not being tight enough etc. The symptoms are an obvious wet trail of water on the sill of the door when opened (where the 2 bits of sill plastic cover meet towards the front of the car), the rubber seal which sits above this sill has water in it, and the carpet immediately inside the foot well adjacent to this area is wet. The leak is not motion/parking angle related - a load of water came in during recent heavy rain with the car parked flat on the driveway.
Same on the passenger side, though not leaking as badly - though the leak is more obvious as it makes the plastic heel protection bit on the drivers side (not present on the passenger side) shiny when wet.
I did want to check the front drain channels weren't blocked as a first step, but I failed miserably to get the wipers off (despite soaking in penetrating oil, wiggling like a madman, persuasion with a rubber mallet) so this will be my next avenue to go down with my local garage if replacement membranes don't fix it. They get all the jobs I fail at
Nearside membrane now replaced - was fairly painless as I only did the sound deadening mod a few months ago.
Excellent YouTube video explaining how the door card comes off: https://www.youtube.com/watch?v=Djgcv-VpCW8&t=221s
I bought in advance: new door membrane, 6m * 8mm butyl tape, pack of cheap white and yellow trim clips for the door to replace the couple which broke off last time the cards were off, or any newly broken.
Door card off - note the membrane is cut through the bottom and up around the airbag. Tsk.
Membrane removed, shows the original placement of butyl.
Butyl removed - followed a tip I read about using a ball of the old butyl and, as it likes to stick to itself, using it to pull the remaining mess off the door - it works like a charm and makes it all very easy and quick. I cleaned up any remaining minor traces using a lemon oil based sticker remover I had kicking around in the garage - in hindsight I wouldn't bother as the old outline gives a good guide for the new butyl.
New butyl bead added. The top right had side corner needed to be at more of an angle so was lowered after this picture - partially because I got it in the wrong place

but my new membrane was also at a slightly steeper angle. In hindsight I would either use a thicker tape than the 8mm one used here, or (probably better) do two widths worth of a 6mm tape. Hopefully this will be fine though.
And finally the new membrane added. There are cutouts on the left and right hand side for wiring and in the middle for the airbag connector, so you should not need to make any changes as long as the airbag is disconnected (do so after disconnecting battery and wait 25 mins - do not reconnect battery until the airbag is reconnected or you will trip an airbag light which needs INPA/a dealer to remove). If the airbag is left connected, you'll need to enlarge the central slit so it is large enough to fit the airbag through.
After that pic, I added some gaffer tape just to cover the bead poking out at the top right hand side so it doesn't stick to the door card - the trailing wires on the right also show here hanging down, whereas there is a plastic plug I had forgotten to push back in, through the foam, into a hole in the door.
The only other thing worth mentioning is that the new membrane has no holes present for screws when putting everything back together - I didn't make any specific holes, just screwed everything straight through the foam and it all went back without issue.
Not sure if this will fix the leak or not, so have a fresh dry towel sitting inside the passenger footwell ready for a nice heavy storm to see if it gets wet or not
