You do have to take the laterals off to get the center off. Start in each wheel well (there is a bolt there) and work towards the rear.
You may have to destroy some bolts, so get extra.
Biggest pain was pulling the plastic step molding to get at those bolts in the corner. They are held on by plastic split-tongues that stick into square holes in the bumper. Best way (I think) is one person underneath squeezing those split tongues together while someone else pulls up on the molding. Or it may never go back on tight again. Like mine.[/QUOT
You DO NOT have to pull off the side pieces. I replaced mine several months ago. You can kind of push the plastic split tongues from beneath the bumper to get the plastic piece off. I used a plastic trim tool - like what you use to take door panels off- to get it off. Once off I used Dupli Color black bumper coat on the piece and it still looks great. The four captured bumper bolts are 8 x 1.25. You can buy the nuts at Home Depot or Advance Auto ahead of time. Even with using Kroil ,the four bolts that go in the Y shaped body mounts had to be cut off with a grinder. Mine were very rusted.
I hope this FSM diagram shows up: