Depends. If you are running factory size tires with no lift, +1 will probably work, and +20 will be about the same as your factory setup (wheels are wider, but tires will still be centered about the same). If you are lifted 2" or more, +1 will definitely work with factory tire size, and you could go with slightly wider tires with little or no trimming required. I think -12 would require trimming regardless of tire size and amount of lift (unless you go with something like a 6" lift). This is all based on my experience with my current setup. Others may have a different experience as there are so many variables when you consider variations in alignment, uca setup, etc.