Paragraph 3. I found that the instructions for the parking brake doubler plate called for mounting it on the front of the firewall. The design of the S20 has changed from a flat one piece firewall to a 3 piece design with stiffening ribs and details stamped into it so the doubler can not be used on the front side of the firewall. I had to modify the shape to be able to use the doubler to install it on the inside surface of the firewall.