experiences towing with 3.5L ecoboost

I am amazed at the power my 2013 has. It outpulls my single valve V10 with no trouble. Mine is used to pull a 17' horse trailer that weighs about 5,500lbs with one horse in it. The only issue is that the rear suspension is a little soft when pulling. I replaced the rear shocks with Rancho 9000's and it helped some. The real solution would be to use a load distributing hitch or get max payload package. I would expect the Flex to be even softer but might still be adequate for a 2300lb trailer. Just keep in mind that you probably will be much more in control with a load distributing hitch and good trailer brakes even though they may not be required. Also, your trailer will weigh a lot more than 2300lbs when embarking on a camping trip. Since I need two tow vehicles I plan to buy a second Eco-boost as soon as the max payload package is available and replace the old V10. That might tell you how much I like the Eco-boost.