The squeaking when braking is normal and is because the SS comes with metallic brake pads and need to be bedded every so often. Once the pads have been bedded this squeaking will go away for few months till it needs to be done again.
As for the squeaking while driving, can you describe it? Is it a intermittent sound "squeak. squeak. squeak" which could be a warped rotor or is it one long "ssssqqqquuuueeeaaaakkkkk." which could be a stuck caliper.