@ 4.56 gears, your motor will rev about 200-300 RPM higher on the highway at all speeds.

so pretty insignificant in my eyes for the performance gain

 

Not really, my XLT came with 20's and 3:73 LS.

 

oh i am more than sure i can live with that!! for sure!

 

My 06 fx4 came with 20's and 3.73LS.. I thought 3.55 on fx4 was an option and 3.73ls was standard.. I've been wrong many times before. just ask my wife

 

Speaking of going off topic. I have a 2015 f150 lariat crew with fx4 package. It has 20" tires and 3.55 rear end. And is a 145" wheelbase. I have a 34' travel trailer and it's all over the road even though my truck is rated to easily pull the weight and i use sway control bars with weight dist. hitch. Does anyone know how i can change things up to pull this camper (rear end, tires, is wheel base too short). I would hate to think i need to trade up to a 250 if i don't need too.

 

Wrong section, but look into this system:
Roadmaster Active Suspension Kits | Helper Springs | Overload Springs

 

Off topic and nine years late.
First question is - what is the tongue weight of the TT?
Second question is - what is the weight of the TT?
If your tongue weight is less than 10% of the trailer's weight, it is going to be prone to sway. You may need to move some of the load from behind the trailer axels toward the front.
Next is tire pressure - ensure all tires are the correct type and size and that they are all inflated in accordance with the weight and capacities sticker (usually found on the outside of the camper, inside the main entrance door, or inside a kitchen cabinet).

 

mine came with rims and tires lol