run php code upon cb subs subscription completed for specific subscription

I need to run a small piece of PHP code when a user completes the payment process (when the subscription is made active).

I have done code autoactions before, but I'm not sure

1. The proper trigger (I read elsewhere that it should be "onCPayAfterPaymentStatusUpdateEvent" is that correct?)
2. The proper conditions (and syntax) to select when the subscription has been activated AND when it was for a specific subscription/plan

You can use the below to act on plan state in CB Auto Actions. In your case this would be with a Code action and Method set to PHP.

Plan Active
Global
Triggers: onCPayUserStateChange
User: Automatic
Access: Everybody
Conditions
1: [var3] Equal To PLAN_ID_HERE
2: [var2] Equal To A

Plan Expired
Global
Triggers: onCPayUserStateChange
User: Automatic
Access: Everybody
Conditions
1: [var3] Equal To PLAN_ID_HERE
2: [var2] Not Equal To A