The first time I saw the pictures it was hard to wrap my head around it. Most GT3 and GT4 cars look very professional and serious especially when the cars are low, long, super aerodynamic supercars (which most of them are). On the hand, the Mustang is based on the GT350R and the body shape is so different. It does sort of look like some yob has thought "let's make a JDM car but instead of J (Japan) it'll be A (America)".
It will begin racing in the 2019 season of the British GT Championship. Despite what was said above this thing may have a really good chance because it was developed by the same company that did the Ford GT and the Chip Ganassi racers that battle it out in the FIA World Endurance Championship. Oh yeah, the Mustang has already won IMSA Continental Tire SportsCar Challenge.