As Hohn said, I LOVE my MT/Rs. The 315s fit just fine on the stock alloy wheels. Yes, there is a slight rub on the lower control arm just before full lock. There is also some rubbing on the back of the wheel well (the part thats flat) at full stuff.
The Nittos look like a good tire if you spend all of your time on pavement. If you don't, you may want to look the BFG ATs or Goodyear MT/Rs. Amazing as it sound, my MT/Rs handle much better on the pavement than the stock Michelins did. And when it comes to off-road, there's no comparison.
Another thing that amazed me was that I didn't notice any loss of power and even increased my fuel mileage with the 315s.