I think it's best to have an even tension on the springs, but it shouldn't matter too much if one is a little tighter than the other. But as the other person mentioned, the springs really don't have much to do with the action. That's just a matter of getting the trem parallel to the body and adjusting the trem posts and the
truss rod. Those will all affect the action and height of the strings. Of course if you have the tremolo spring too loose, that will raise it from the body and make your action too high. if they're too tight and the trem is going back too far, you'll get buzzing because it is too low. So in that respect, yes it will affect the action. It's a somewhat delicate balance of tension between springs and strings.
John