He asked what was really needed, and with the WC none are.
But there are plenty of options to make the kit a little better.
I too have the Kawahara Pinions*/Brake Disc*/Rear Sway Bar* also the Square ti rear dog bones and drive cups, Evola Springs, 2 kit rear shock towers glued together to reduce flex and a 5th body post.
They were not needed but they do help make the car easier to drive.
*not yet run