Firas Abd Alrahman

Once you install WordPress with some plugins and finish customizing your theme, you usually stock with performance issues. 
Installing and configuring a good caching plugin, you will enhance your first byte and website speed, but you getting low rank on google page speed. 
The reason for that, each WordPress plugin come with it\’s assets (js/scss files) and most of them are not really used or required, but WordPress does not offer a way to control those injected files in your themes. 
GSP Assets Manager offer an easy way to list, review and control WordPress assets. 
You can disable, move to the header, move to the footer, toggle async for javascript and WordPress without writing a single code. 
The plugin also offer a live preview for CSS, so you can disable the CSS file and see the result directly on your website before you save, to avoid breaking the website style.

GSP Assets Manager (Easy Live Assets Editor)

GSP Assets Manager will allow you to live review and control WordPress javascript files and stylesheets. Optimize google page speed rank within 5 minu …

Scott Taylor

Similar to what we use on eMusic – this software is still experimental, but take a look!
Automagically concatenates JS and CSS files that are output in wp_head() and wp_footer() – stores / serves them from Memcached (if installed) or Database. In a load-balanced environment, the generation of flat files can be expensive and hard to distribute. Minify takes advantage of Memcached and Site Options / Transients to do the work once and share it among all servers in your cluster. File names are dynamically-generated to allow cache-busting of a CDN like Akamai that doesn’t always cache-bust by query string.
New .htaccess rule! 
 RewriteRule ^([_0-9a-zA-Z-]+)?/?wp-content/cache/minify-(.+)-(.*).(css|js)$ /wp-content/plugins/minify/make.php?hash=$2&type=$4&incr=$3&site=$1 [L]

Minify

Automagically concatenates JS and CSS files that are output in wp_head() and wp_footer()

GSP Assets Manager (Easy Live Assets Editor) vs Minify