Sorry, I can't edit the post. You do need a Torx T20 for the 6 outside screws, and it can be used for the non-security T20s on the inside. Here's a set that has T10-40 Security: http://www.amazon.com/Torx-Driver-Security-T-10-T-40/dp/B0002SPLQ8So what size Torx do we need? You link to a #20 driver and a set that doesn't include #20...
I would have been done by now but see my Torx aren't security bits.