Originally Posted by DaveK

While we're speculating on the cause (mine was cracked too - replaced it last fall), I would guess that the most likely cause is slamming the trunk lid. Considering how many have cracked, I find it hard to believe all of those owners have driven it fast enough to produce the kind of downforce necessary to produce the problem, and I would think one hard trunk lid slam would produce a tremendous amount of force on those wing struts, considering the amount of overhang of the wing from the mounting points.

I know I've been very gentle when closing the trunk lid since I've replaced the wing! I would recommend others do the same...

Just my $.02 worth...