[fauXGT]

But just stretching the fender looks like it creates a flater top edge, which throws off compared to the front fenders sweeping arch. It would also stretch the wheel opening. The z cut could be utilized, but would be very difficultly scary.
I would rather try to fix existing panels than to drastically modify and make look factory some things that are curvy in all directions...unless you've got it figured out already.