i agree with everything being said. i'm running 35's, but i've got 4.10's. with a superchip, i have no plans on ever gearing lower.
i wouldn't be suprised if the 35's themselves dont void the axles. wheelin' my jeep stock i never broke anything. with 35's, i've broke a u-joint and ball joint. i wheel like an idiot though. my jeep leaves earth more than most due to my heavy foot, but still. something to consider.
you NEED a lift in addition to other suspension components to run 35's. this will probably void the drivetrain and most suspension parts.
3.73 is really pushing it. with my 4.10's and chip, i have good power, but my MPG is like 12-13. i'm wheeling alot, and if i kept it on the street i'm guessing it'll be 15-16 maybe.
i too would reccomend 33's. with proper trimming, no lift is required. i doubt the dealer would b*tch about 1" over stock tire size either, and you'll see better MPG's. 33's will go places 35's will, it just takes a little more finesse. i like monster trucking everything. i bought my jeep used, and i had 4.10's. no warranty, good gears, D44 rear end, i had nothing holding me back. even MPG i could care less about. it's a jeep. i expected shitty gas mileage when i bought her.
my advice...get 33's. if you wheel, get a trans cooler, gusset your C's on the front, buy some plates and armor, get a superchip, and save up for a nice lift. by this time, you'll need new tires, and be out of warranty...and you're set up for the 35's just in time.