I somehow wonder why would anyone run a GT wing on a car that isn't an actual race car and one that is actually too big to actually go racing. If you've ever sat in the F10 5 series you'd know that it it actually as large as the interior of a F01 BMW 7series. This is because the F10's chassis is based on the F01's chassis. Hence the luxury of space inside one. The only race that the car could enter safely and not look like a sore thumb or like Lady Gaga at an awards ceremony is at the Australia V8 supersaloon races.
Anyway, the car is a grown man's sports saloon and it should not have goalposts sticking out of it. Also note that AC Schnitzer has not really gone overboard with the exception of the rear GT wing. And they have also shown the car san wing, making it look very much like the stock car with the exception of the larger wheels ans tyres and that ridiculous stickers at the sides of the car. It shows that the standard BMW M5 looks pretty good as it is and does not need any extra help in the styling department.
I however do dig that funky engine cover that could be an option for a customer to purchase.