The dashboards are made from four layers of fiberglass. It's strong so you won't get any problems when the electronics or a tv / tv's are installed. Most openings are already open, which will save you a lot of work, but to make the overlays for the electronics perfectly fitting, you probably still do need to sand the edges, so the overlays will lay perfectly flat against the openings in the dashboard. The lines that you see on the dashboard are seams from the mold itself, because the mold exists out of several pieces. The seams can be easily sanded down again.