It is likely to be your rear window leaking...more specifically the soft top portions on either side of the window. The rear window piece is separate from the top. There are several YouTube videos on it including one or two with repair ideas. Over time, there are several small places in the fabric that fray and wear thru. My 2K leaks as well. I tracked down the frayed/worn thru spots and made some temporary repairs with marine silicone and duct tape...it slowed the leaking, but did not completely cure it. The bottom line, based upon your description...you will need a new rear window section. I need one too, as my repairs did not hold. See if you can google up the videos and/or find the worn spots on you rear window section. Cheers!