I know this is an old post, but if I need a new rear bumper anyways on a 2005 4.4i and am wanting to do the 4.6 kit with the wheel arch flares on the side...wouldn't I just order the 4.6is rear bumper 51127062598 (instead of the 4.4i one) so it already has the side slots for the bumper supports? It should install fine on a 2005 4.4 shouldn't it? I want to say that the rear bumper was the same from years 2001 thru 2006, yes?