@bertoost
I see what you mean about the menu, I don’t really know how to achieve that with Wayfinder! Wouldn’t rule it out though
Have a look here and see how your setup compares:
http://modx.com/revolution/developer/requirements/
I’m not really sure how well your snippet is optimised. Perhaps you could limit it to only looping through the resources that you need, rather than everything on your site? You seem to have a lot of products on there, and if it’s going through all of them that could be slowing things down quite a bit.
If you only need the categories for the menu perhaps you could include a WHERE clause in your query to include only the product category containers, and only go a certain level deep ... something like that? It seems to cache ok though, right?