The turbo Supras love higher RON fuel. I could easily notice a difference, plus you're risking detonation with anything above stock boost with any other type of fuel. Some would say you're risking det even with stock boost on a Jap import.
The non turbos don't seem to show any benefit.
I can't really see how the engine could re-adjust to the higher RON fuel quickly without risking damage to itself. It would surely have to advance the timing in very very small increments or something. If it just went "oh, let see if we've got better fuel yet.. advance all the way. DET. oops, nope, still shit fuel, almost broke a piston" it wouldn't be too good.