If you remove the brace, the mount holes (and the spot weld holes) will guide you back to the exact position where it attaches to the tower top. Nothing says your patch has to be as big as ITHURTZ's. So no need to cut all the holes and everything away on yours. You could scribe or draw an outline, too. The point really is just that the overlapped replacement metal should go on from the bottom for best structural integrity. If the GM part for this is $80 thats what I would want, to save time / labor even if all I did was to cut a patch from it. As you see, it isn't easy to match that shape. Welding inside the right rear strut tower from the wheel side is safer in terms of distance from potential spark damage / hazard, than welding inside the trunk. So plan that way if possible.