I would go with 4:56s if I were you. If you are saying your truck drives nice then whats the big difference between 35s and 37s other than a little weight? You are already stepping up from 3:73 to 4:56s.. thats a big jump. I would just say that if you do alot of highway driving then you should stay with a numerically lower gearing. If you go with higher then you will turning some big time RPM's going down the highway which will lower your MPGs even further. I guess if you care about the mileage then that could bother you.

I have 35x13.5s and 4:56s and I love the pick up they have and everything, but I wish my RPM's were a little lower on the highway. Its all up to you though, thats just my 2 cents.

 

4.88's are what you want, everyone is so afraid of gears and it's downright disgusting when people are posting mileage and performance gains from steeper gears but that old wives tale of the lower the rpm the better the fuel mileage on the highway