285s is the largest I would go. 305s (on 3rd gen steels) rubbed on mine pretty bad. I really like the look of a 305

 

i Ran 315/75r16 Baja Claws on my 97 single cab 4x4 on stock rims with no problem at all
no leveling kit. but using a stock rim wears tires badly in the center because they are too narrow for a 12" wide wheel. also depending on the TRUE tire size makes a difference too. just because i had a 315/75r16 micky Thompson you can change brand and the true tire height and with can change. i have 33x12.5-15 pro comps on my jeep and they only measure 31.25" brand new even thou they call it a 33

my advatar is when my truck had the 315s on it