The stiffness of a kevlar part is in between fiberglass and carbon. However, making a stiff part is not normally why kevlar is used.
Its anti shatter properties are the main reason for its use. It is much more difficult to use compared to other reinforcement fabrics due to how hard it is to cut and how hard it is to tidy up the edge of a kevlar part.
If you are buying kevlar fabric, we have 2 options for cutting it, 1/ manual kevlar shears or 2/ Electric scissors.