I have been planning to do the rear disc upgrade for some time using the SSBC kit. Other things took precedence.
To get the most out of rear disc brakes some brake bias can be transferred to the rear brakes. In my case I removed the EBCM and installed an adjustable proportioning valve. If you want to retain the ABS I believe the EBCM can be reprogrammed (or have some settings changed) to accomplish the same thing.