My 2 door Rubicon is still on the stock 4.10 gears. I have the Hutchinson/35" Toyos as well as bumpers, spare, winch, recovery gear so it's a heavy combination.
I was set on re-gearing but after adding the Superchip Flashpaq the performance is such that only rarely do I have to downshift to 5th.
I do a fair bit of 80mph commuting in the Jeep, and the 4.10s aren't bad there, it's about 2800rpm on the interstate. Gas mileage sucks with the air resistance, gears won't change that.
I really investigated the possibility of going to 4.88 or even 5.13 gears. The Jeep runs very well on the interstate at 80mph in 5th, which is equivalent to 6th with a 4.88 rear, but it's at over 3300rpm, but not really a problem with the little V6.
The difference between 6th in the manual and OD on the automatic is astounding. A buddy regeared his auto to 5.13s with 35s and he now runs about 100rpm more than me on the highway!
Another guy put 5.13s in his 6-speed with 35s, compared to mine he has essentially lost 1st gear on the street, and doesn't have an OD for the interstate now. But it is great offroad and his 4-HI is terrific.
I am still torn between regearing to 4.88s, or keeping the 4.10s and going with an atlas 4-speed case.
I would like to do both, as there doesn't really seem to be a downside to the 4.88s even for interstate use.
Unlike Planman, I really don't do rocks, and I do a lot of 80mph interstate miles, and secondary 65mph, not as much in town.