Lift is not the issue for the most part. The 305's will probably need a small lift but you can run 285's with little issue unless you disconnect and off road.'
The biggest issue is they will rub while turning. The 305 is too wide for the stock offset. I ran 285/70/17's for awhile. Didn't notice them rubbing until the shop put it on a lift to put on armor. They were barely rubbing on hard turns and was wearing the inside of my tire causing tire damage. I had to add 1.5" spacers on the stock wheels to save my tires.
There are some that say they haven't seen any rubbing with 285's but most of the time they will. It depends on the tire. But 305 will definitely rub when turning
Here is were my 285's rubbed