I've installed most of the brake duct kit on my '05 GT... and yes, I do track the car.
I did the 14" Brembo upgrade a few weeks ago. I managed to get the exterior plastic for the 2011 Track Pak to fit the opening in my lower outside grill. At least on one side. Destroyed the driver's side one before I figured out a better way to make it fit. I'll finish up running the hoses when I procure a replacement.