I have 3 custom SCT tunes from Mike but only use the "Economy Tow 87 octane", it increased my towing mpg by aprox. 10% ( from 8 to 9mpg). You will like the increased torque off the line. Mike matches the tunes to your trucks PCM/ECM model number so you will have to remove it from the firewall to read the numbers. (10 min. job)Thanks for the link westxsrt10. As a FTE member that is my plan. Incidentally, my ex son-in-law was an engineer on the Viper project. Used to bring home vipers for me. What fun..