I've got to say the Subaru Rally WRX Impreza from the mid-1990's was pretty unstoppable in FIA Rally course. Obviously, the Rally car isn't designed for crawling over obstacles like a lifted Jeep is but then again you probably would be doing a 120-130mph on an unprepared surface like the Impreza can.

https://www.youtube.com/watch?v=eTrBxVtQbe8

However, the best of both worlds-- Current 7 time Champs of the Dakar the KAMAZ...

https://www.youtube.com/watch?v=8FcEuuakWPg

It can do a 130mph in the open and crawl over rocks too...


I do have to ask one question like the kid if you are doing mostly highway driving why get the 37's? If it is just for the looks okay. You'll need to get a pinion puller for the pinion gear. As for gears get the best ones you can afford. Make sure they have a lot of contact between the teeth when they mesh. That way you will distribute the torque across the complete surface of the tooth. That is important cheap gears tend to have less contact area and can easily damage the teeth under high torque loads.

Here is the truth about gearing a truck-- you really need more than just a change in differential gears. You really need to change the gearbox gears as well. But no one does that-- unless you are a rally racer. Because you need to change the torque rise between each ratio to really get the best performance for your vehicle. The charts for tires and differentials only give you an approximation of the normal performance of your vehicle with the stock stuff. Since I don't care about top speed too much-- I always go for mechanical advantage. I would pop- 10:1 differential gears into the truck if I thought it would give me the Earth moving performance I wanted in 3 feet of snow or mud. But that is me.