Nope. Depending on your driving conditions, the springs may wear down your shocks faster than the stock ones. If one of your shocks mysteriously blew out then your dealership probably would not replace them.
we just had the Eibach pro lowering springs put on my 06 cobalt ss non supercahrged and i love it. it lowered it just over an inch in the front and almst 1.5 inches in the rear. and it wont void your warranty.