so, my JK isn't here yet...so i can't poke around it. i rely on your expertise.
on the TJ's, when we went up to 35's, a lot was required (not just lift, sye, control arms.) but things like brakes and steering also had to be addressed. 35x12.5's would tear up the stock steering pretty quick, and braking was downright hazardous.

the question i pose to you is this...
will these things also need to be addressed in the JK? i won't be going any larger than 37's

 

The only thing i would suggest is new track bars. especially if you ever plan on running 37's. The factory's are just not built to take the punnishment of wide tires. I don't have my JK yet so I wouldn't know about anything else at this time. I have heard that anything higher than a three inch lift requires some new brackets for your brake lines. I'm sure if it needed to be replaced on a TJ you might as well replace it on your JK. just my .02

 

What about the Rubicon Lockers? I know the TJs started to fail when the tires got much bigger than 35.