The black plastic piece that the license plate bolts to and the turn signal attach to. You can remove it and put the license plate on the side and move the turn signal in or get the integrated tail light turn signals.
I know this one cause I just broke mine and had to replace it. For the '07 models the braket for narrow tire models is part# 69051-07A and for wide tire model part# 69086-07A. They both cost $50.50 before tax.