The Extremis is going to be the 6.5" version. It won't have the fancy phase plug for a couple reasons that have to do with break-up nodes and maximizing the Sd of the driver for 2-way applications.
It also has less usable high frequency bandwidth due to higher inductance but you don't want to use a driver that large full range anyway due to the narrowing polar response as you get higher in frequency.
The Extremis 6.5" should be available in a few weeks.