First off, Welcome to WF
What gear ratio is in your jeep? and what transmission do you have (standard or auto). Also, have you picked the tire that you want? All tires are alittle different even though they say 305/70R17, they may actually be smaller than that size. With the 4" backspacing on a TJ with that size tire you'll prolly have some rubbing issues while steering to full lock, which is fixable by just adding some washers on the steering stop, resulting in having a slightly larger turning radius. and if you do some hard wheeling off road you'll prolly want to add a 1.25" Body Lift to that to keep from stuffing the tires up against fenders. More than likely you'll wish for a gear change.
Do you realize the cost difference in 33x12.50x15 tires/wheels as apposed to 305/70R17 tires/wheels? It's pretty hefty price hike, the 305/70R17 is a 33.5" to 34" tire depending on what tire make and model you go with. In most cases it's $100 more a tire, plus the added wheel cost.
Last year, I bought my 33x12.50x15" Goodyear Duratrac tires mounted/balanced on new 15x8" Dick Cepek DC2 wheels (3.65 backspacing- no rubbing) for a total of $1326- shipped to the house. (tire warranty included in that price)