Well its RARE for sure takes good tires/driver. Fastest LS4 powered car that i know about is a cartuning's turboed Monte SS running 11.49.

My DA corrected time for my best run is a 13.73. But i have Tune, Cutout, CAI. And honestly i dont know if i could run that time at sea level since i dont have a problem launching at 5000+ foot here in colorado. where as at sea level id have to worry about a good launch to duplicate that time.