[Performance] Getter/Setter vs static

[adi4x]

I'm staring to make an AS3 game. I want to know something about performance. Here is my (theoretical) case.

Classes
Main.as Hero.as Ghost.as

The game action is simple: the Ghost must chase the Hero (and has to know its X Y position).

1. How to send the Hero X Y position to the Ghost(s) ?

1. Using getter/setter
2. Using static var - this seems easier

2. How many enterFrames events to use
Instead of making classes with their own enterFrame events maybe i should keep one class Game.as and search for collisions using a loop
Or maybe I should use one single Timer event ?