I do know that with too much back space the AR rims will hit the calipers but that is 15" not sure about 16's.

I assume they mean they can shave them so no rub. I don't really see a problem if shaveing but too much could be a problem.

I would suggest just get a BS that does not rub. They may stick out and give a wider stance but that is what most of us have done.