I'm going to install 14" chubby apes on my '07 fxstc. Is a one-piece clamp necessarily reqiured?

 

Not necessary if you like having your bars twist around on you. With high or wide bars and the stock rubber mounted riser bushings you will get movement, too much for my liking. A 1 piece riser top clamp, like the factory piece, will eliminate most of the movement.