That rough area in your paint, if along the bottom of the door, could be the infamous 'orange peel' effect I read about in some other car forums. This was said to be done purposely to a car in order to hide everything from scratches to dings from road debris as you drive your car more and more. Not sure if this was ever talked about here. A lot of people expressed dissapointment about it, but ultimately, didn't become too much of a issue.