Quoting From The Edge EZ Manual: "We recommend level 1 or 2 for towing applications. Only use level 2 if you are towing a light load. Level 3 should never be used while towing. Level 3 is a great overall driving level. When driven responsibly, and used with an EGT gauge, level 3 will not stress the stock engine or transmission as long as you are not towing."......Nuff said.