Water
 

Ok... So did some research on this water that keeps showing up behind my driver's side seat and still have no idea where it's coming from. I checked the drain holes and even put an air hose to blow out a debris in them. It start raining this morniing and again water collect behind and under the seat.. Any idea what I can do ?

Check out this post http://986forum.com/forums/boxster-general-discussions/17685-water-under-seat-solved.html

I've got my fingers crossed that this was my issue and will know for sure tomorrow.

I have a couple of ideas.
First, open your top half way and check to see if the convertible top is attached to the two plastic clips. If not, the water will not drain into the drain holes.
Second, if you have a top with a plastic window, see if there are any areas where water may leak through. Even if the hole is small, this can lead to water behind the seat.

Eric