The rear stock tower brace is absolutely a waste of money, Unless you are running a rear coil over shock set up. To be honest, the front shock tower brace is also, because your tires will start to scrub way before struts in the towers start to flex. If the Challenger has a unibody, then go with the full matrix sub frame connectors that also employ the jack rail set up. This would not be a waste of money, but the sfc's will add about 50lbs to the weight of the car.