A siderail member for a subframe assembly of a vehicle, including: an elongate body, wherein the elongate body includes a hollow extruded structure including an inboard wall, an outboard wall, a top wall, a bottom wall, and one or more internal walls. Optionally, the bottom wall has a thickness that is greater than a thickness of the top wall. Optionally, the outboard wall has a thickness that is greater than a thickness of the inboard wall. Optionally, the one or more internal walls include a top internal wall and a bottom internal wall forming a plurality of horizontally-disposed cells within an interior of the elongate body. The bottom internal wall has a thickness that is greater than a thickness of the top internal wall. The hollow extruded structure is manufactured from an aluminum material. Optionally, the top wall of the hollow extruded structure defines a flexure recess.