just got my car two days ago. has hks hi power exhaust. thought i had a serious problem because there was some serious knocking going on below my car, but a little looking around and i figured out it was just the pipe hitting my rear dif and possible a part of the rear subframe. i repositioned it and all the clunking went away. for a day, now its back. how to i keep this exhaust from moving around in the hangers? thanks for your help!