The S197 (2005-2010) cars have a significantly more rigid chassis so at this time for street, autocross and open track cars we do not recommend any frame stiffening.  This however does not apply to race cars as you can never have a chassis that is to stiff in a race vehicle.  In race applications we first advise you to concentrate on removing excess weight since the vehicle is heavy in its stock form.

Please do not fall for the gimmicks that unscrupulous companies are trying to sell. The only thing you will get from subrame connectors or frame stiffeners on an S197 Mustang/Shelby is a heavier car and a lighter wallet.   

For more information please review the following:

"GR40 Kit for 2005+