Keep in mind for future upgrades, SD is not as forgiving as MA. The Mark VII wiring harness goes through the firewall at the upper, passenger side. Click on the image below, the engine harness is in red.
The harness is held onto the firewall by a large rubber gasket/o-ring. It is deisgned to be pushed in from the engine side, and will NOT easily come out. You might want to bring some WD40, and in the worst case, a razor blade.