Your carpets could also be wet due to leaking door seals. That is, they have shrunk.
Here is a tried and true way of testing if you have cabin leaks. Go to a carwash bay, put your air conditioning on high, and get out of the car (while it is still running), and shut it up (don't lock yourself out!!!). Hose it down real good with soapy water, getting it around the seals.
Watch for air bubbles forming.
Where bubbles form...is where air is coming out. Which is where water will go in when the cabin isn't pressurized or equal pressure, and where you will hear whistling when the vehicle is on the highway.
Used this method to track down noises and leaks at a body shop I used to work at.
Welcome, downwardly mobile yuppies, to the dawn of the Age of Nefarious.
1993 SSEi - FrankenJinx - dead and gone.
1994 SSE (136K strong) - 180* t-stat,HD alternator, most unequipped SSE on the club, XM radio, Kenwood CD/MP3.
2006 Chevy Malibu Maxx LTZ - Custom 2.25" manifold-back exhaust w/FM-80. Probably the only Maxx with this system.