Wheels are fine, have similar myself. Stick on some 245-75-16"s won't affect the gearing too much, had them on wifeys for a while. BUT with the wider offset wheels you will need to trim the bottom of the front bumper a touch, about 1" IIRC, its not as drastic as it sounds, easily done with a stanley knife.
Tyre wise, always difficult, I like the old grabber AT2s, the wifey wagon now has grabber ATs on, seem okay on the road, not tried them offroad yet. I am going to give a set of cooper ST-MAXX tyres a go on my MJ when its roadworthy, getting good reviews
