I've only had my exhaust move on me once. I'm running the Injen system w/ race style single tip and Cobb hangers. I don't think the single exit style is capable of hitting the valance though. It slid towards the inside of the car. I only caught it 'cause I heard the S bend banging on the underside of the car. I was able to use some cut rubber hose that fit snugly on the metal hangers to keep everything in place. Never thought to use a set up like the set screw collar. Great idea. Using the rubber tubing I've had good luck. If that changes, I like knowing of this option.