I was fortunate enough to have attended the Ford Performance Racing School in Charlotte, NC driving Dark Horse GT's around the Roval. We tested the pre-collision braking system at up to 25 mph and it worked each of the 4 times I tried. The key is it only engages if there is no input to the...
Had a similar issue and was asked if I garage it with the top down, which I normally do. Leaving it parked for several days with the top up allowed the fabric to stretch into place. Now it closes completely. Just need to remember to park with the top up every now and then.