And then let our production axle housing rust
All black exhaust does look good though

 

ah, now i understand what those right & left vertical slots up front are for... Ford just released more 2015 design details;
Using air to manage airflow
It’s not visually obvious, but rotating wheels are a major source of aerodynamic drag. However, enclosing the wheels in skirts to smooth the flow just doesn’t look right (e.g. 2014 Z/28), especially on a performance car like Mustang. Widmann and the aerodynamics team adopted a different approach for Mustang, giving it the first Ford application of wheel aero curtains.
Vertical slots in the outer edge of the front fascia channel air from the front of the car to openings in the wheel wells, directing it across the outer surface of the wheel and tire. The wall of high-speed air works much like a skirt to reduce drag while still leaving the beautifully designed alloy wheels fully exposed.

 

...wind tunnel graphics illustrating air flow;

 

more aerodynamic info (clock mark 4:13, there is mention of "performance pack vehicles", possibly GT350 or mach1?);

 

Performance Pack relates to bigger brakes and slightly uprated suspension.......rather like the old Track Pack