In an embodiment, a side door for a vehicle can comprise: a structure comprising a plastic inner shell comprising a fiber strip, and a plastic outer shell comprising an outer shell support beam positioned across a width of the outer shell. The outer shell support beam can comprise a fiber strip with ≧50 wt. % fibers oriented at an angle of less than or equal to ±45° to a main axis. In an embodiment, a method for making the side door for a vehicle can comprise: flow molding a fiber-reinforced polymer over a fiber strip to form a plastic inner shell; flow molding a fiber-reinforced polymer over a fiber strip deposited to form a plastic outer shell, wherein the outer shell comprises an outer shell support beam positioned across a width of the outer shell; and joining the inner shell and the outer shell together to form a composite structure.