Yes you are correct the stock wheels are a +30 and the aftermarket wheels have a 0mm offset.The new tires have a tread width that is quite wide because of the aggressive tread,so the 0mm offset helps the tire clear suspension parts. It also gives the Bronco a nice stance.
Yes, yes & yes. I just put them on over the weekend so I haven’t had a chance to go off-road with them. They are loud but not as loud as you would think. They are heavy, but only noticeable when accelerating.