Joe Souza reduction drive

[overtime]

I have been running a Joe Souza redrive on a Subaru EA81 for a few years now and would like to obtain a replacement Mercedes flex coupler and splined 3 arm rotor for the drive. Joe was active in both gyroplanes and hotrods and my searches within these interest groups for contact information have all deadended. So does anyone know:

1) what model and year the drive coupler is
2) contact information for Joe Souza