hi frosticek

priority should be-
 1- script
2- css
3- js
your theme is creating issue !!! seo

osc_enqueue_script & osc_register_script

<script type="text/javascript" defer="defer" src=""></script>

how wil we defer js and css, or async!

<script src="js/plugins.js" defer></script>
 not possible to do <script type="text/javascript" defer="defer" src="<?php echo $this->getSkinUrl()  due to osc_register_script


js and css causes a delay in rendering my page!

cannt able to add async.  cause link href,  #<link rel=#  such option is not available. 

@russia
We are using built-in osclass functions to load styles and scripts. Consult with osclass.