I know there are a lot of problems getting the rear bumper to align nicely with the body. Sometimes the problem is the reproduction bumper and/or brackets. My bumper was not aligned well...the bumper was a repro and so were the brackets. I found an original set of brackets, straightened them and restored them. I used them with no additional washers, just the wavy washers installed between the bumper and brackets(one at each location) and the bumper fit perfectly. In my case it was the repro mounting brackets that were the problem. Thought I'd share this as I know how many cars have misaligned rear bumpers and how time consuming it can be to try to correct it.