Improved performance and stance compared to prior offerings Allows full range of adjustment with stock Cobra Jet rear suspension M-5649-CJ Excellent upgrade for 2008-2012 Cobra Jet or any 2005-2013 Mustang set-up for drag racing As used on the 2013 Mustang Cobra Jet program Made exclusively for Ford Racing by Eibach with proprietary Ford Racing specifications Replaces M-5300-R Cobra Jet spring kit with new rate and ride height for rear springs