Which Flex for a Towed?

I think it is time, the 05 Saturn Vue is beginning to show it's age. I would like to tow the Ford Flex with it's 7 passenger seating. But which model has the lowest curb weight. I will "test drive" any serious considerations to the local scales, but I would like a place to start. If you currently tow a Flex and know it's curb weight could you please tell me which model...eco boost or standard engine...which wheel configuration?
Thanks