In Poser 6, without hand editing of files, the V4 base and morphs did have to go in the application folder. Poser 7 would allow the use of external Runtimes as long as search behaviour was set to shallow, and from Poser 7 SR3 an external location could be used regardless of settings (though as hborre notes all of the morphs sets and the base must be in the same Runtime). As WandW says the Installed Programs window is overstating the size of the installed files anyway.