Slowsol, unleaded 100 octane is NOT cheap. When the ECM is tuned to 100, it gets WAY thirsty when you get into the gas pedal. REAL thirsty. From the standpoint of how the car feels on the street, a good 93 octane tune will be plenty, and then you are not tethered to Sunoco stations. I don't have Sunoco available in the KC area, so I have to drive 20 miles for VP100 at $9/gal, so you can trust that Streak now just sits between races. Over the winter I will switch my tune back to 91 octane so I can street drive the car on pump gas.