So today was the day to install the 4th brake light. The install went easier than expected. On iJDMTOY's website there is install instructions:
http://store.ijdmtoy.com/Valenti-Sty...tion-a/617.htm
On my 2019 86 the wiring was different. The OEM brake wire color is
GREEN. The OEM tail light wire color is
RED. Just an FYI to check your wires before installing as things change model year to model year and car to car. What is so on an FR-S doesn't mean that it will be the same on an 86 and a BRZ.
Don