Nope, didn't have to modify the fender wells at all. I angled the bottom, where it welds to the frame, so I wouldn't have to cut the wheel wells... I have since seen some posts on here that show a little strengthening of the frame where the shock towers attatch, I guess on retrospect I would do that as well. For me, I guess it's too late..ha ha But I haven't had any problems yet(knock on wood)