I am lookin to purchase the H & R super sport springs...I have read on a few websites that you must change your panhard bar when lowering 05-06 mustangs. Is the true, or are they just tryin to upsell products? Do I HAVE to purchase a panhard bar in addition to the springs? Thanks for the help.

 

You should get the panhard rod when you lower it because the rear will shift to the right the adjustable rod will allow you to recenter the rear tire's mine shifted 3/4". You should also get a upper panhard support the stocked one is only made of stamped metal here is the parts numbers [PHR006 Tubular Adjustable Panhard Rod $129.95 ]
[PHR007S Upper Panhard Rod Support $99.95 ]