If you were at three springs (common), you may not like the feel of four. You can move the two outer springs so they hook into the outside holes on the tremelo but leave them in the middle hooks on the claw. This will angle the spring and stretch them out a little more, maybe giving you enough tension to level your trem without adding more springs.
Although not as fluid a feel as a three spring trem (with lighter guage strings), I do think four springs (with heavier guages), aid in trem return height accuracy and helps limit the other strings from going flat when you're bending notes. You will also break fewer strings.
I once thought a "Sweeping Arpeggio" was an Italian janitor.
