The roof I got will just be used for individual parts. If the original metal is intact, it stays. I don't want a big shear line of weld where I butted the two sections together. The inner panels of the frame are almost untouched except directly over the 1/4 window. The lower panel of the upper windshield frame is fine, but I'm replacing 1/2 of the upper panel. The sides will get new drip rails, and get the outer panels replaced with parts from the donor roof. At no point will the continuity of the perimiter be broken.