I bought an electronic version of a manual for my 2005 WRX. It's also got info. for the STI. It's very detailed with everything you can think of, install, removal, diagrams, etc. I'm happy to share it with anybody. It's 148mb compressed. PM me if you want it. It's in sections, so if you need something specific I can email you a smaller piece.
Again, note that this thing is 148 mb, and it won't fit in an email box. You'll have to come by my house and get it on CD, or send me a link for an FTP site for upload.
http://files-upload.com/133268/WRXSTIManual.zip.html wait 25 seconds, then click the link towards the bottom left