I don't know what flares and wheels you have on your rig now but if they are stock and if you want to keep the new Ion's and tires under your current fender flares then that backspacing is a major concern:
..if it is 3.5' on an 8" wheel vesus the 5.25' on a stock 7" steel wheel like I have on my '98...then I think they are going to be sticking out.
At a 'NEGATIVE 27mm (a little over one inch)' offset on that Ion wheel you will have a lot more of the wheel moved out away from the TJ chassis. My stock TJ steel wheel has 25+ mm (right at one inch) of POSITIVE offset so the stock wheels are position in closer to the chassis and under the flair.
So those ION wheels should be sticking out over two inches more than your stock wheels do now...that excludes any additional distance caused by 10.50 tires. If that is the case, those wheels definitely would extend beyond my stock flares.....
Sooo..Before you give up any of your hard earned green for those wheels..I would have one mounted up and put on you Jeep and see what you have....good luck.
'98 Sport 4.0 - Auto, Hard/Soft tops, Dana 44's, 3.73's, Mostly stock...