Sharepoint Services v3 and Portal 2003

I want the document management enhancements of WSS v3 but do not yet want to run MOSS 2007 because of higher licensing costs. Will the SPS 2003 install and operate properly if WSS v3 is already installed? Is this a huge no-no? I can’t seem to find reference any where on running WSS v3 with SPS 2003.

– jason