Well, it depends on your welding skill. In general, the original metal fits best. Second gen Barracudas have large low crown panels, so it is more difficult to hide a seam. Less filler is better. A butt welded seam with no distortion is ideal, but difficult to achieve in real life. I don't like to cut out straight, un-rusted USA metal and replace it with something that was stamped in China, or even Ireland. That's all of them. But I'm weird that way.
