It helps align your suspension geometry. If you find you are getting really bad bumpsteer after a good alignment and the CC plates and all... get it. I didn't have it on my last car and that was lowered about 1.5" up front. No issues but 1.5" is about the limit before you might want one.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.