Cusco is offering a "Power Brace Rear Trunk bar Plus" for the A90 Supra platform:
Power Brace Rear Trunk bar Plus now available.
TOYOTA GR Supra (A90/3BA-DB model(DB42 / DB22 / DB82))
Steel oval shaft
Product Number: 1C2-492-TP
By installing the optional power brace seat rail plus front and seat rail plus rear together, it is possible to install the racing harness without drilling holes in the vehicle body. (In the case of 5 points or more, it is necessary to replace the seat with a crotch belt.)