RD Sport was the fully forged (center and barrels) division of Racing Dynamics. Actually the forgings/barrels/hardware are all Kineses and Racing Dynamics America commisioned them to build these parts. Unfortunately, there was personal conflict between the people running the two divisions and now it is virtually impossible to get these wheels anymore. It is too bad, I love the wheels and they are quite strong without being heavy. As far as I know, they are the only Z application ever built. F =19x8.5 ET30 with TONS of X-factor R = 19x10 ET 44 also with nice caliper clearance.