Another reason to do torsion bars before sway bars is, soft torsion bars can allow the stiffer sway bars to break their mountings. This is because of the longer suspension travel that soft springs can allow. Sometimes the through-body sway bars will tear through the body like the topic below, if you have the bars set to max stiffness and the sway bar geometry doesn't allow for smooth, non-binding movement.
Sway bar pulls through tub sheetmetal