haven't been to the dealer. the guy I bought the car from had the gt500 bumper installed and it has been like this since. I looked at the brackets that hold the bumper in place and they seem fine so I'm not sure what the deal is.
Both sides are the same, as well as the rear bumper, which hasn't been taken off or modified in any way.
you dont have it on all the way.. that lip going into the wheel well area needs to be pulled to the rear of the car more and then pushed in. It should be on the other most rear part of the splash shield and metal. easy fix.
Just undo the screws on each side and maye a flat head screw driver for prying. . its gunna be tight.