I have a 2DR Jeep with the 3.6 L. Its a great engine. In 2012 there were some issues with the heads up until about July 2012.
I have a 2013 and its great. Pulled from Wisc. out to Moab...them to Durango CO ...up to Ouray CO and back home not a problem.
The big thing you need to check is the rear axle
ratio. I have a 3:21 and I get about 18MPG while towing. That rear end is geared for mileage. I have researched and I would have been better getting a 3:73 rear axle
ratio. It would provide better towing ...but lesson learned. Don't get me wrong the 3:21 works fine...it's just that the 3:73 would be better.
As far as the engine...it's fantastic...but that isn't what provides the torque for towing....it's all in the drive train.