Originally Posted by 808MGuy
Like others have said, it is the weak link because it is designed to be that way. The way it fails is actually a safety feature which keeps you from losing control of the car. The OPs situation definitely doesn't look normal and does appear to be caused by someone prying on it which I have heard is common for some inexperienced installers to do when installing springs.
His car looks exactly the same as mine, hence me posting in this thread.
It boils down to this - if you strengthen everything else in the suspension and leave the weak link the same, the weak link will deform at a lower load than the overall weaker system (i.e. in the non-M).