Max, when going to less backspacing, you run a higher chance of rubbing at the fender and back of the front wheel wells. I am assuming you are sticking with the 33" tires. As long as you are only stepping back to say 4" of back spacing (from the factory 4.5"), then you shouldn't have that big of an issue. BUt then, this also assumes you are sticking with the factory width rims. You start going to a wider rim, all the increase in width is going to occur on the outside edge of the rim, pushing the rim further out. The further out the rim is, the more likely you are to get rubbing.
Of note, if you go with an 8" wide rim with 4.5" of backspacing and a 33" tire (aka 285/75R17), you will only have to trim the front valance and that is about it (easy thing to do). Keep in mind that this assumes twisting the truck up to its limits. I ran 315/75R16's on the stock suspension and 8" rims for a month. I only got rubbing on the back of the wheel wells when I got the truck on uneven ground (say trying to make a turn while starting up a hill).
If you can, give me a little bit more detail about what you are looking to buy and I can hopefully give you a pretty good assurance as to whether you will get rubbing or not.