In my '99 stock speakers were.......
Dash 4 Ohm
Door 2 Ohm
In doors, I tried Infinity Kappa, Polk and I think MB Quart 5.25". To be honest w/ you, I don't specifically recall which was which but rather they were all underwhelming.
When I finally did it right w/ baffles, I used Infinity Kappa 6.75" (2 Ohm)
I appreciate where you are coming from on the time factor. I travel a ton and my Boxster, though I love it, is not a daily driver. It's stored Nov-April and LY I put less than 3K on the clock.
Anyhow, it will not take you much longer to make baffles than to swap out the existing speakers in the "tuned port" b/c in either instance, you not only have to pull the door skin, but also need to put on new connectors for the speakers. The baffles are mirror images of each other so they can be cut/made at the same time. You may easily be able to find a retired woodworker, etc. to make them for you.
Here are 2 guides to help you - a comprehensive DIY guide and a template for the baffles.
http://boxster.wikia.com/images/b/b6/Boxster_speakers_update_article.pdf
http://boxster.wikia.com/images/b/bf/Door_Baffle_Template.pdf