Alright just like the title says. What all goes into fitting a rear bumper. Say I bought an aftermarket one and it needed a bit of "fitment" before I painted it. What would this all involve? Like are you just sanding certain edges down slightly for a cleaner fit or is there serious cutting of edges involved and such. I am not afraid of sanding a bit here and there. I guess I just want to know the whole process and be prepared for it.