Categories and large number of products

I have imported 60,000 of my 130,000 products so far (including categories), each product appears in two categories, but as you can expect, I'm seeing a little slowdown (nothing drastic or that I didn't expect), but I was wondering if anyone had any tips to reduce this.

 

Firstly I would like to remove the dynamic sub-categories from the Browse by Category menu, as I think that would reduce the XML file size and thus performance ?

 

Secondly I would also like to remove the Search results by category: from a search. Try Arsenal and you will see what I mean, as it returns all categories where Arsenal appears and that will be alot (causing un-necessary load on the search)

 

Finally, for the time being (until I finished the upload or see a MASSIVE slowdown), how can I force the user to type at least 4 characters in the searchbox before pressing search, as I see this as a potential killer query if you type just one letter and hit search

 

 

 

Think I have managed to do point 1 already, I will now attempt points 2 and 3. Thanks for the pointers

 

I've managed to import over 131k products and I still think the performance of both frontend and admin is acceptable, I do have plans for more products so no doubt it will become a problem eventually ?!?