33's yup but with a 31" tire you would have plenty of clearance, The gearing would not need to be messed with, the cost would be less, you would only loose 1" of clearance, but they would not look as good! Tug[addsig]
33's might fit but it will be a street jeep. You generally need a minimum of 4" for 33's and probably an inch or 2 more if you offroad much on a YJ anyway. TJ's can fit a bit bigger tire with less lift because of their flares. I would suggest 31's or maybe 32's but I think 33's might be too big. I have a 4" lift and 31's and have absolutely no clearance problems at all. When I upgrade to 33's I am going to put on some TJ flares for extra clearance and maybe a 1 inch body lift.[addsig]