Hello Nino, first thanks for your purchase.
Regarding performance, there are a few things you can do after you finish your website. For example, there are several different ways to compress and combine the assets, this is probably the easiest way: http://www.okler.net/forums/topic/minify-php-how-to-combine-minify-and-cache-javascript-and-css-files-on-demand/
The images can also be improved, consider to export them in a lower quality. JPG 80% is good enough.
Regarding the cache, this is the right way to do that: https://developers.google.com/speed/docs/insights/LeverageBrowserCaching
You can also remove the plugins that you will never use in any page and combine/compress all the other scripts so it will cache the resources and make it much better in performance in any other page.
The use of a CDN to serve your website files also it’s a good idea.
It works the same way for all HTML templates. All files come uncompressed to make it easy to edit and customize, and then when you finish your website you can make the improvements.
We hope this helps.
If even so you still wants to contract a freelancer to that, we work together a developer that has advanced knowledge with our themes. Feel free to contact him for customized tasks. His email is [email protected]
Let us know if you need further assistance.
Kind Regards,
Rodrigo.
If you are satisfied with Porto HTML and our support, please leave your comment and rating on ThemeForest downloads page. That helps us a lot: https://themeforest.net/downloads