What you trying to achieve is far beyond the capabilities of this plugin, I'm afraid.
- ~400 item isotope grid needs insane amount of cpu power to handle. Isotope is very powerful, but not that powerful. 99% percent of your visitors computer would not be able to handle that.
- ~400 items possibly with images will take dozens of seconds to load on a single page and again, will cost the visitor terrible amounts of Ram and time
- As far as I can understand you are trying to filter results by multiple requirements (by price, color etc…) – that requires a lot of programming knowledge and a plugin designed exactly for your needs – in other words, there is no plugin available for doing this exact task. You might need to ask a freelancer to do this for you, he can maybe use the Related Posts Pro plugin code as well.
I'm not saying this is not possible, but I'm certain that you need a custom made plugin for this task – I'm saying this out of my years of experience with wordpress.
The best idea is probably to make something ajax-powered (like search engines, or some kind of ajaxy content), so the content of 400 bikes is not already loaded and taking up resources of the users computer.
Usually I'm able to make some small changes to fit the plugin for the customers needs, but in this case I would need to rewrite it completely.
I'm very sorry, but I think there is no way to configure the plugin the way you described. Perhaps you can still use it in your site as a simpler related posts widget.Best,
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