There is more to lowering a car than just lowering it. When lowering either by the use of aftermarket or cutting stock springs, a set of aftermarket cast/camber plates is recommended so the shop can do a proper alignment otherwise, the shop will be trying to perform a factory-spec alignment which may be impossible in most cases.

The shorter springs change the angle of the strut which has always been an issue with lowering Mustang and and other Fox-based platform. The factory plates do not allow much strut adjustment which is what the alignment works off of and Ford didnt design the suspension with lowering in mind. Aftermarket caster/camber plates will fix that.

Hlistr_07RR - 'cc' stands for caster/camber.

 

How much are they and how hard are they to install? Google here I come
Edit: 164 from American Muscle for the cheapest ones they have. Hmm. I don't want new tires to wear funny so I prolly should get them