I was not able to find anything in terms of css and javascript aggregation.
Drupal does this wonderfully via a drupal_add_head() function that is used by themes and modules to add css and javascript to the head of the site. The theme then prints out a $head variable, instead of the hard-coded css and javascript includes.
This allows you to enable a perfomance option of aggregation and compression. This then combines the files together, saves them on the server and links to the aggregated files instead of the individual files.
This results in huge performance gains, especially if your site is using a css grid and any jquery plugins. Since each one comes with its own file and sometimes css styles.
I will do some research into how Drupal processes the css and js files. But in the meantime, any feedback on where this fits into processwire would be appreciated.