There is no reason to run a single bead lock. The guys you see running singles are rock crawler guys. Why they do it, not sure but for what we do, both sidewalls take just as much impact.
As for the locks.. they do add a little bit of weight and are a little harder to break loose on the track. They become consistent in the fact that you are not gaining the wheel spin as quickly as you would with a lighter wheel which reduces the chance of lost traction and a more consistent race car. This is seen more on a guy running a smaller tire. If you are a cheap SOB like me, you skip the locks and throw a set of big Hoosier 34.5's at your ride. :lol: