unloading dlls is definately not a good idea for most people.
when the os is not using a dll. the memory is allready released
when the os is using a dll, you do not want to unload it, do you
pretty simple, and this tweak is counter productive
there just aren't too many actual performance tweaks that do anything for xp that prove beneficial to most people
they were concieved before x... people just continue to use them as if they are a holy grail
pretty much the only thing you can really do to help this os is set ou the interface as convienently as possible
that will speed you more then even valid tweaks
things like putting your often used utilitiies at your fingertips, and stuff like that
never the less, this guide is an amazing resource, and it will continue to be an abundant download.