i have an 07 gmc sierra crew cab and i have been looking for off road fenders. I have the larger bushwacker fender flares but honestly they dont work so well, my 35s rub all the time and im still getting rock chips. Ive noticed fiberwerx has a set of off road fenders for a silverado but not for a sierra so what im asking is will the silverado fender work on my sierra and do they actually work?