Youre collecting the new GL series as well? Are these new upgraded versions of the Manhunters?
But as for Quasar's auto defoence....
He has preprogrammed them to be sensitive to incoming energy fluctuations of sufficient power to do him harm and automatically absorb that energy. He also programmed his quantum-bands to automatically whip up a forcefield when it senses an incoming energy source that may be harmful to Q's form.
He cannot program his bands to automatically protect him from danger from non-energetic sources. Thus they cannot automatically protect him from ballistic objects (kinetic energy is not part of the electromagnetic spectrum). Thus a bullet could catch him by surprise but a laser blast couldn't.
He's also programmed the quantum-bands to automatically protect his mind from psionic influence by producing a jamming wave in his mind.