I already installed the lower radiator support in my GTX. I have the fender bracing but I haven't installed them yet as the car is already painted. I don't want to mess with the paint but I will. If you have the dash and windshield out you can also weld up the cowl lip, the steering column support And any where the seams are spot welded. Just doing that made the whole cowl so much stiffer. You can also run weld the frame to the floor as the spot welds let the body flex too much.