I just got rid of most of the fender lip on my wheel wells. They were cuting into my 18's and it was upsetting. So I took 3 hours and took each rim off one at a time and power sanded the fender lips in. It is not that hard. I also cut out a little of the wheel well with tin snips. I have a pic of my car and also talk about it more in the topic MY 18'S FINALLY FIT in this wheels and tire forum.
Peace