It is using an integral link rear suspension (likely a high-performance evolution from the AWD versions of the CD platform.)
2015 Ford Mustang Rear Suspension Photo 10
And they redesigned the front. No longer a lower control "A" arm. They are using the dual control link like on a lot of the higher-end MacPherson strut equipped cars... M3, 911, etc.
http://www.musclemustangfastfords.co.../photo_11.html