If your "JDM diff" has disk brakes, you will need the matching hand brake brake cables. And you will need the short hand brake cable that goes to the handbrake lever. Im told you can use one off a SV11 Camry.
If you have disk brake rear, you will want to play with the rear brake limiting valve in the engine bay. It is easiest to open it up and remove the spring and rubber valve to start with.