230kph - SCTEX on the MX5. The car could do more but I just went back to 100 after that for two reasons. (1) At 230kph I could already feel the lack of rigidity and (2) I was afraid I would get caught.
Normally, I wouldn't really go over the speed limit but for that brief moment I desperately needed to know what the car could do
My dad did do 200 on the Fortuner and it still feels stable but you could feel a bit of lack in power. @SCTEX
Nissan Terrano - 150kph @ SCTEX
Corvette ZR1 - 280kph @Autobahn (a relative's. which it was mine though