If we could find a rebuilder who does the actual rack you have that would be the best answer for the Mark VII owners. There are still plenty of good cores to build left, as yours is most likely. These are taken better care of, far better, so they could last as long as needed. It's the rebuilders who mix all racks up that are the problem, none of them you find easily will rebuild yours. They send you one and take yours as a core, so you have no clue what the new one is(obviously from a Mustang and wore out before).
I'm aiming at the 03/04 Cobra rack, as being the best(tightest/feel etc), but rebuilders do the same thing with those. There is a casting number on them, but the rebuilders can swap any internal parts, so you cannot know what you get even when they say it's from the right application. The Cardone unit is a 222000 part, but most examples turn out to be regular racks(minor differences but the road racers can tell them apart). I have an AGR rack I bought new, not wanting to risk going through the rebuilder deal, but this one is a bit stiff for my liking, made that way I'm sure, but I've driven an 03 Cobra and I think I'd prefer that OEM stiffness.
1991 Red Special Edition, my 2nd SE, dead paint, DWS 255/45/17's on 95 Cobra wheels, and soon; DVD/Navi/backup camera, OBDII and the 347, before custom paint.
98 Mountaineer with Continental DWS 255/55/18's, big sway bars, custom brakes. Soon to be A4WD with XP8 bumpers and wing.