I have always used premium in both the SRTs. About six months ago I went on line and found a pure gas dealer in my town. The no ethanol pure gas wakes up the coupe. It is a difference I can feel and at about 10 cents a gal over premium. I used to get between 220 to 230 per tank with the ethanol premium, now I am going 260 to 280.Give it a try and let me know what you think.