A nice table at the bottom of this
page about exhaust size and the torque.
Given the fact that our 2012 FF is a CID 121 et le the best exhaust diameter for it seems to be 2"-1/4 or 2"-1/2.
Edit: changed the CID to 121. Because of the HP, I think the max for the exhaust of the FF would be 2.5"
White Platinum Metallic Tri-Coat
303A, 6-Speed SelectShift Automatic, 17" Aluminum wheels, Luxury Package,
Parking Technology, Navigation, Winter Package
Chevy Volt 2014, White Diamond, Luxury Package, S1, Navigation.