Your 17 has the .ecoboost engine vs the v8 in your 07. Two totally different drive trains. The 3.31 gears with the v8 will struggle much more than the same gears with the turbo motor, because the ecoboost has much more torque at much lower rpm. To tow adequately and comfortably with the 5.4 you should have 3.73 gears. Seeing 3k rpm while towing with either motor is not a concern and either motor can tow that way all day and all night without issue. My 5.4 (with 3.73 gears) would tow at 70mph in 4th gear at 3k rpm without issue. The ecoboost (also with 3.73 gears) pulls the same load in 6th gear at 2k rpm.