4.88 is way overkill on the 2012. I have 4.10 factory and 35's. I have plenty of power going over mtn passes and cruising lowland flats. Thats all you need. Depending on where you live anywhere from 700 to 1000 per axle.
That's one opinion. I've spent the last week in the heat between 5000 and 9000 ft with a 2012 manual trans with 4.10s and 35s and I've been wishing desperately for lower gearing.
Looked at gear chart and there seems to be about 170 RPM difference at 70mph between the 4.56 and 4.88. With the 6speed manual trans. I am having the same deliema between 4.56 and 4.88. My 2012 is a daily driver with 35s and I want stock performance and mpg. I do plan on occassional trail riding and mudding with buddies. I was tod 4.56, but they are a little more expensive than 4.88. I have to be cost conservative.
I can only attest to what works with the auto but there a lot of members here that have manuals that can help you.
I personally donít go by gear charts for my final decision. I like to rely on what the vast majority of people are saying to what gears they are running with basically the same setup as mine. You also need to factor in the extra weight youíll be adding to your Jeep like bumpers front and rear, winch, roof rack, under armor, body armor, tire and wheel weight and the list goes on.
As far as something being a bit more expensive donít let that be the deciding factor on which way you go. For the most part, whatever gears you end up installing is something that you will have to live with for as long as you own your Jeep. Be smart and chose wisely.