Edit GameObject.Variable

Hello unity 3d i want GameObject.Variable edit in other file;

i can GUIText edit but no gameobject or prefab in variable edit;

my codes;

var SpeedOfMeter : GameObject;
SpeedOfMeter.speed = 1;

Not working.

i’m add PlayerCar gameobject in SpeedOfMeter prefabs folder.

My SpeedOfMeter Packes ;

http://forum.unity3d.com/threads/63885-Car-speedometer-dial

Best Regards.

http://docs.unity3d.com/Documentation/ScriptReference/index.Accessing_Other_Game_Objects.html