[Blas]

I'm no FFR expert, but if the photo in your gallery is you and your car (Color coordinated outfit?...nice..hehehehe) there appears to be a lip in the front of the hardtop extending ahead of the windshield. I would think it becomes a spoiler of sorts, adding pressure to the window frame and lift to the top (protrusion of top acting as "wing") Test the theory by putting some racing tape along the window/top seam to divert the air. Don't stick it to the top or the test will be invalid (cause of the extra anchoring of the tape - frame to top) Just to see if the air diversion solves the problem...Bring your fast hands with for the test, but I'll bet you won't need them....but if you do, then body flex, windshield design, mounting hardware, will be the next thing to look at. I would guess that driving without the side windows would be a major disaster with this problem unsolved...due to the added air pressure underneath the top...
If that does the trick...adjust the angle of the windshield to eliminate the hardtop's "lip" that extends beyond the window frame - no spoiler means no lift...
Good luck...