what is your lowering combo? when I went with eibach and illumina I had to use some large fender washers on the top nut because the threads didnt go down far enough to keep tension on the spring. might be worth investigating. another thing to check is the upper ball on the rear endlink. make sure its not making contact with the inner wheel/frame area under compression.
It ended up being not enough tension on the spring. I have no clue how to fix it as, like 323 said, washers were added. Its a huge gap though