Has the car been in an accident? Is that why the door hits the fender?

If the fender's not messed up, you should be able to loosen the bolts that hold it in place to make minor adjustments. I honestly don't know where all the bolts are that hold it on. You'll have to look around and likely need to remove the fender well insert. As for downsides, it may cause gaps and other pieces (front corner, headlight, sideskirt, hood) to not fit correctly. It's definitely a give and take situation. You're going to have to identify the lesser of the evils and commit to it...