25 mm front bar and 26 mm rear bar which are smaller than 1SS bars.
http://media.gm.com/dld/content/dam/...under-2013.pdf
* 85 percent stiffer front springs, and 65 percent stiffer rear springs, are optimized to match the new DSSV dampers
* 25 percent stiffer lower trailing-link bushings on the rear suspension improve lateral stiffness in cornering and reduce wheel deflection during hard braking
* 50 percent stiffer lower-arm link bushings on the front suspension, improve steering feel
* 400 percent stiffer rear upper control arm bushings improve lateral stiffness to cope with 1.08 max-lat cornering
* Smaller stabilizer bars (from 28 to 25 mm front; 27 to 26 mm rear) are tuned to match the reduced rebound travel