Start here: Direct instructions to eliminate porn from results & add all the words into your keyword filter from 'both' links within that post.

Then also: (a) Problems with the search, __ (b) Hostiles List (LW must be closed when you add this hostiles file .. so wait until you finish your session to do this.)

Oh .. almost forgot .. keep an eye on these file sizes & also the auto naming technique of spammers in your search results via these examples of commonly spammed Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see)

(BTW Performance options are to do with your connection to the gnutella network, not with search quality in the way you thought.)