The 3W dashboard is 42.5" wide and the 5W dashboard is 41" wide. That's the easy part. The distance from dash mounting point at the belt line to the firewall is at least 2" more for the 3W. As a result the 3W dash is deeply dished so that the oval opening meets the instrument panel. By contrast since the distance is less for the 5W the dash is therefore relatively flat. Also, the 3W dash mounts on an angle corresponding to the cut of the door while the 5W dash mounts vertical which also corresponds to the cut of the door. Is it easy? yup, if you have a 55 gallon drum of elbow grease, a bundle of determination and a lot of time and money.