Your profile says you have a Sport, but doesn't indicate what gears you have. Sports come standard with 3.21s, but have an option for 3.73s. The 3.73s on a 6-spd should be fine. You'll probably lose 6th gear around town, but it'll still be useful on the highway. With 3.21s you'll be struggling a little and lose 6th gear completely. You'll probably be wanting to re-gear sooner.
On the trails, if you crawl, you'll want to re-gear with either.
Get the 35s and you can always re-gear later.
2018 JL Rubicon Unlimited, 6-speed, White
1985 CJ-7, 4-speed, 258 I-6, 3" Springs, 33" BFG AT, Gunmental Gray