Abstract: A modular vehicle door has a hollow door shell of sheet metal panels that are secured together at their abutting periphery, a crash beam that is attached to hollow door shell so as to extend across the length of the door, and a module that supports several parts of vehicle door that is preassembled and assembled to the hollow door shell as the preassembled module. The hollow door shell has a hinge reinforcement at a forward end and a latch reinforcement at an aft end. The module has a metal support beam that is attached to the hinge reinforcement at one end and to the latch reinforcement at the other end so that the metal support beam extends across the length of the door and forms a box section with the crash beam. The metal support beam has upper and lower channels and the module includes an insert molded carrier that has a plurality of ribs that cooperate with the channels of the metal support beam to increase the torsional ridgidity of the metal support beam.