Cold Air Intake, Worth it?

I tow a travel trailer with my 2008 T4R V8. Around here in East Tennessee I can get about 12-13 mpg towing it. The trailer's gvwr is 4950 lbs. and I would estimate that fully loaded it weighs in at 4700-4800 lbs.

With all the hills and mountains around us more horsepower would be welcome. I've heard and read a little about cold air intakes and was wondering if one would make much of a difference in my 4R. I don't want to compromise longevity of the drivetrain. Anyone have one on their 4R? Would a CAI do the trick and what should I expect to gain from one? Is it worth it?

Thanks.

You can get a little horsepower from it, but you won't notice it unless you have occasion to really get on the throttle. Probably won't have any effect on your mileage. Not worth it in my book. A more efficient exhaust system would be much more productive.