Here's the link to the Durametric site. tons of info:
Diagnostic Tool for Porsche | Durametric
The enthusiast version (max 3 vins) is all you need and you can often find one here in the buy/sell section with only one vin used up.
What you described is basically it: a cable you hook up between the car and your laptop via usb using their software. It allows you to read and clear CEL's, airbag lights, you can do all kinds of diagnostics, turning things on and off. You can even turn on your onboard computer display if you don't already have it. No Boxster owner should be without one. It's like having a tricorder.