Curt Tow Reciever
Factory wiring is a great way to go, perfect fit, good instructions, plug and play.
I agree with removing the bumper. The fish line in theory would work, but in practice I found I was not able to get it inserted past the Styrofoam alignment tabs on the Energy Absorber that are pressed into the aluminum bumper reinforcement (the tabs block the channel). Once the Styrofoam was removed, it went well.
After the install, I wish I had just paid the extra for a factory receiver. Better fit also.