Really depends on what you want to do and how aggressive. There are different schools of thought on the issue. I'm pretty happy with a 3" lift and 33's. I run 285/75/R16 Duratracs and so far have been happy. I considered going up to 315's but 33's seem to be the sweet spot for me when it comes to overlanding. I'm not into rock crawling. Just like to get off the beaten path and see the sights. On other overlanding forums, I've read people are plenty happy with 33's too. Also depends on what your rig is geared for and what engine you have. Performance is going to be impacted greatly. Plus, going to a larger tire size is going to wear out parts faster. I had my front Dana 30 sleeved and gusseted because I was going to run 35's. Even with 33's I'm glad I had it done. Going to larger tires means you may need new wheels, modify bump stops, etc. And of course, the ever expensive regearing to accommodate larger tires. Also, buy a pro cal or something to change your shift points when you move up to larger tires. Also expect your mileage to decrease as well. I gained a little bit back with the pro cal. But not much.
