Thanks Erik
, most of the pictures i can find show, and intuition says that they should be vertical for the most torsional (edit: actually bending not torsional) rigidity to the chassis, and though they could benefit locally, from a stability stand point, if they are slightly angled. Although increasing the angle means increased material, and increased material means increased weight, and i am pretty sure we know Mr. Murray's thoughts on adding weight. The main reason I ask, is because the picture of the care being assembled which show the front bulkhead without the crash structure installed show the mounting points for the crash structure to appear as though the inside is angled, and the outside is vertical. See the pictures below: