i have the same problem, everytime my car is in rain stuff on the right side of my trunk gets soaked. I've just been too lazy to look into it. So if you find out lemme know..
1998.5 Diamond White Pearl SVT (#4725)
custom exhaust/intake k&N/mod'ed y-pipe
slotted rotors/greenstuff pads/SS lines
cougar trans/FSVT shift tower/Torsen
16lb. flywheel
18" Velox VX-8's with some rubba bands