The Scamp has an 111" wheelbase as compared to 108" for the Duster/Demon/Dart Sport. I'd expect the Scamp/Dart to pack more than 4 pounds over. The roofline of the Scamp/Dart is wider and longer which certainly adds weight. The floorpan is longer, the drive shaft is longer, fuel and brake lines too. The Scamp/Dart has roll up rear windows as opposed to simple pop outs on the Duster. I'd be surprised if the Scamp wasn't at least 50 lbs heavier.