I did this on mine. (Look avatar). The diff in height on extensions is there, but it also exist on the grille.
What i did is remove the rectangular brackets tubes, and replace by 71-72 ones. On these, you need to cut the lip bellow for like 20 cms, so it can rest on the body frame and enlarge/relocate the first hole to reuse the bigger 73 bolts. The bumper itself will be like 2cms lower to body than on 71-72 and be rotated 2 to 4 degrees. To me, it looks far more better than the massive plastic piece that kinda ruin the line. There is some visible space that then appears between grille and bumper, as the grille is unlike previous years very thin, that could be filled to look nicer. Say, something like the plate between rear bumper and body on 73.