Thanks so much for your help, and I really appreciate everyone’s comments! I know the 4.0 is not the most powerful engine, but have been driving them in my XJ and TJ for 25 years, and never really “needed” a regear to keep safe highway speeds in CO until got my LJ with 285’s about 6 months back. I really like my lift height, and may be able to fit 34’s with some highline fenders in the future, but wasn’t really planning on 35’s at any point. Sounds like 34’s may put me in between ratios (4:56/4:88) otherwise my gear selection would be much easier (4:56 for 33’s, 4:88 for 35’s) Yes, gearing is expensive! That’s why I’ve been obsessing about it for months, since I only want to do it once! While living at high elevation with hilly terrain all around seems to play a role in my decision, I don’t want to be overgeared to the point where I can no longer go 80 comfortably (I get that I will have peak HP at 4500rpm, but driving over 3500rpm for extended periods really sounds loud and feels inefficient on the highway). Would be nice to keep it in 5th going 60-75, and have 6th gear still be effective and comfortable for 75-85. I get that the automatics need much deeper gears than manuals, but most of the advise I have received shows 4:56 for 33’s (either with the 5 speed or 6 speed). Looking over the gear ratio calculator, the 6 speed seems to need one step higher gears to be at the same rpms (3000) at 75mph (4:88 in AX-15 5speed = 4:56 in NSG370 6 speed). While I’m leaning towards 4:88 (with the logic that they will accommodate larger tires In the future), I’m worried that 3700 rpm at 85 might not work well for me.