Pete, just remember that if you go to an independant shop you'll have to pay a Ford dealer to re-flash your tune for the differant gears. Unless you are getting a real tune. I've driven the V6 with the 2.73 & 3.31 and bigger is better. I would like to try the 3.73 but have heard enough stories about noise to make that mod unlikely.
2012 V6 traded in for a 2017 VW GTI.