[Brad]

We build an array of templates before including global.php for one reason: so we can pull all these templates with one SQL query.

If you do not include a needed template in these arrays, vBulletin will have to run an extra query to fetch it from the database. This means there will be more load placed on the database server.

If you add a new custom template, and fetch it via a plug-in you'll need to also place that template into the cache array. You can add new template to this list by using the hook: cache_templates.