Best place to add custom curl script after payment completes

I'm looking to add some code once the user completes payment successfully, ideally before the render method for common/success.tpl is called.

Is the file catalog/controller/checkout/success.php the best place to run this code? It's a simple curl post script to send some user data to an external form. There is no need for logging the response at all, it's a one-way post.

The curl script will need access to the user details such as First Name, Surname, Email, Phone.

I ended up putting it in this file, works a treat!