stock pickups , the ones currently in your guitar are ok but usually not great. by ok i mean they will do thier job and maybe not much more. If u went and got let say a seymore duncan double coil (double coil, humbucker, same thing... :rolleyes: ) that has a high output, youre gonna get more distortion and more volume. every pickup has its own sound to it. your gonna find the one u like

as for single coils and doublecoils, from what i know singles are brighter and gennerally more noisy. double coils are 2 single coils wired together to cancel buzzing noise. double coils have a thicker meaner tone.