Coupe LEAK ! HELP!

[Kwattro@aol.com]

 OK...I took a bottle of water (hot, so I could tell where it was showing
up.)
  I tried the rain channels for the sunroof.  They all seemed to drain fine,
 nothing visable inside.  Do all 4 drain to the front, though?  Next, I tried
 the front passenger hood drain.  It seemed to drain just as well.  Next, I
 tried the door.  Fine, I tried the rain channel along the top of the
windows.
  I tried the rear window.  I tried the front window.  NOTHING!  Am I missing
 something!  Please, all help available.  Crazy ideas accepted.  I don't want
 to rip the car apart, but I don't want the buyer to come back after a
 rainstorm and demand the money back!
 
 Carter Johnson
 Kwattro@aol.com