i just got my 89 gt foxbody but it came with a leaking sunroof i replaced the thick rubber but not the cracked rubber in the picture. i dont no how i would fix it or were to get good supplies please help.
My 1992 has a sunroof as well and just before I got it from my friend he had replaced both the sunroof to body seal and the glass rubber seal that you showed that needs replaced but it still leaked. I cleaned each drain hole and made sure the tubes were not leaking and found that it was coming from between the plastic guides that the front hinge's of the sunroof fit into and the body(one on each side front side of sunroof opening). Check these as well as you check the drain tubes.
Take the sunroof out and look inside the "moat". There are two holes in the front corners and two in the rear corners. The front tubes drain in front of the door and the rear tubes drain behind the door.
Also, you'll see the guides at front. Make sure they dont leak as well. Pouring some water in the "moat" might help track down leaks