well I tried most high octane fuels in my r33, such as Mobil premium, Optimax, Ultimate, And i felt that when i startyed using Vortex98 my car ran alot better, more perfromance, more km's out of a tank, and alot less backfire(hardly any at all). I would strongly reccommend Vortex, but by the looks alot of different people cars run better on a range of fuels. My advise would be to try them all! see how you go.