Can I access a script OnTrigger WITHOUT using getcomponent?

I am trying to optimize one of my scripts by removing getcomponent. Basically I have a trigger, and when certain objects enter it I am accessing that object's script (named "AICar_Script") via getcomponent and changing some variables.

At the moment everything is running fine, but since I have quite a few of these triggers and getcomponent is quite slow I am wondering if it is possible to access the script directly when the object enters the trigger (without using getcomponent each time). The documentation doesn't mention this. Here is the trigger part:

 // Hit the brakes when the AI enters the trigger
 function OnTriggerEnter (other : Collider) {
     if (other.CompareTag ("FastAICar") || ("MediumAICar") || ("SlowAICar")) {
         if (other.gameObject.GetComponent(AICar_Script)) {
             other.gameObject.GetComponent(AICar_Script).Accelerate = false;
         }
     }
 }

I have tried accessing these directly in this way, but I am getting errors on both lines:

 // Hit the brakes when the AI enters the trigger
 function OnTriggerEnter (other : Collider) {
     if (other.CompareTag ("FastAICar") || ("MediumAICar") || ("SlowAICar")) {
         if (other.gameObject.aICar_Script != null) {
             other.gameObject.aICar_Script.Accelerate = false;
         }
     }
 }

In the AICar_Script I have made a reference to itself so that it can be accessed publicly, and I see it getting assigned when I run the the game:

 //Reference to this script so that other scripts can easily access it
 var aICar_Script : AICar_Script;
 
 function Start () {
     
     aICar_Script = GetComponent("AICar_Script");
 }

Am I doing something wrong, or do I simply have to use getcomponent each time when using OnTrigger(whatever)?