Hi, I've read your requirements and I'm pretty sure I can implement what you are after. I have a lot of experience in JS and PHP, and have been looking at your site trying to understand how it works (to save time). There are some things about the project I don't understant, what do you mean when you say "category related specific filters must be selectable on admin panel"? Another question I have is how do you want these additional filters to be displayed? I've thought maybe the easiest thing would be to have in this More Filters menu item a list of sub menu items. When hovering over this sub menu items, a list of checkboxes would appear (DDR3, DDR4, etc...). I think it would be simple and would go with the style of your site.
If you are interested, please contact me. I think the fact that we are in the same time zone is important for communicating, and I'm sure I can do what you are requesting and fast. I have put a week of time just in case something goes wrong, but it shouldn't take that long.