Am looking to upgrade speakers for my RS MY03.
Am I better off getting 6.5" fitted to factory position in rear door or 6"x9" fitted onto parcel shelf?
Keep in mind I will probably also put subwoofer in boot at some time.

RS?

As in focus? Or scoob?

Dunno anything about focus...

Impreza RS is Aussie Impreza with 2.5L motor and same interior/exterior as Aussie WRX just 16" wheels. Good performance without the turbo insurance hassle http://www.scoobynet.co.uk/bbs/images/icons/icon14.gif(although will be improving performance).
Hope this helps with MY03 speaker question.