A method of making a vehicular subassembly includes a step for providing a roof header comprising a hollow member having a long axis, a short axis, and an outer surface that includes a flange. The method also includes a step of stretch bending the member such that the outer surface is substantially in tension and curved in the short axis direction. The method further includes a step of cutting a plurality of notched elements into the flange to reduce strain from the stretch bending step. In some aspects, the step of cutting can be conducted before the stretch bending to reduce strain in the header associated with the subsequent stretch bending.