Hey, what does changing the height of your pickups do?
depends on your action
Makes them more responsive to your picking. You don't want them too high or they will be muddy and you will hit them while picking. Too low and they won't be responsive enough to the notes that you play. Just play around with the screws that anchor them into your guitar body until you find the right spot.
They also kill some of the sustain when they're too high, the magnet pulls the string to itself, shortening it's vibrations. As a general rule to everything, don't overdo it and you'll be fine.
it gives you more or less output. one small recommendation; keep the bridge pickup lower than the other 1 or 2 it prevents electrical buzz from the other two.