It is the typical rust behind the wheels and also around the wheel well lip there is bubbling happening there also. My car was a northern transplant now living in the South. I was unsure that cutting and welding in new sheetmetal would be the way to go because I have heard that once there is rust behind the outer quarter skin, that you can never really get rid of all of it, that it will keep coming back. I am thinking that it would be a better alternative in the long run to just cut out all the old original quarter skin and then take a look at the inner sheet metal and go from there. I believe that the sheet metal inner panels are in good shape in front of the wheel wells but I'm unsure of the condition of the metal behind the wheels. I know that I have to open it up and get in there and find out how bad it is. The area below the drivers side taillight on the trunk tail valance is also bubbling and this valance will more than likely need to be cut out and replaced. I was just leaning towards cutting out the whole rear clip off of the car and starting new. I don't know at this point. The only thing I do know is that this will be EXPENSIVE to repair either way.:(