anyone know of any companies that make aftermarket trailing arms?

http://passwordjdm.com/PasswordJDM-Rear-...4C166.aspx

Nobody makes aftermarket rear trailing arms. There is not enough benefit to it. However, ensuring that your T/A bushings are in tip top shape is huge. This is why companies like Password aka PCI make spherical bearing kits and places like Hard Race make hard rubber ones as an upgrade to stock. As long as your stockers are good though. You'll be alright.