No special tools required. If it's possible, determine whether the rack bushings on the car are 1-piece or two-piece by loosening the rack and trying to pull it forward enough to tell. It makes a big difference when you buy the rack. If you can, .take the rack with you to the parts store, or at the very least the big rolled steel pins that locate it. You'll know what I mean when you get the rack off, they're the sleeves the bolts run through. Take them to the parts store and test-fit them into the rack they try to sell you. They list 4 different racks when in fact there should only be one for a 5.0 Mustang. The rack I bought first was for "performance suspension" and listed a 2-piece bushing. The rack was a dead ringer for the one on my car but the bushings were too small to get over the locating pins. The one I ended up with has a slower ratio but damn sure fit back on the car, so there it stays.
It is not a very hard job, and doesn't require anything special, it's pretty straightforward wrenching and muscle. If all goes smoothly you'll be driving the car again in 3-4 hours.
One thing that really helps is get a can of degreaser and go to the quarter car wash. Spray the whole rack and crossmember area and get it degrunged. It makes things a lot easier to work on when it's clean.
You'll need to undo the tie rod ends by taking the castle nut off the spindle and then give the tie rod a hellacious solid whack with a hammer. It'll pop right down and out of the spindle. Just DON'T hit the threaded upright that the castle nut goes on or you'll wreck it.
You undo the mounting bolts, undo the steering pump lines (wrap them in a baggie or htey'll never stop dripping), undo the collar that locks the steering shaft to the rack's input shaft, and tug and pry until the rack pops off.
The teflon washers are an absolute pain in the ass, but they are necessary. Heat them in hot water to get them pliable and then get them over the line fittings. The trick is they cool off and get stiff very fast so you have to work fast and you have to have a good tapered tool (they sujjest a silicon tube applicator nozle but none of mine were big enough). You'll roll the hot teflon seal up the taper to stretch it, then pop it down onto the fittings. Don't let your neighbors see you becuase you WILL get pissed and you WILL swear like a sailer before you're through.
Next hardest part is getting the steering coupler hooked back up. You have to align the flats, then get the bolt started in the collar again which can be hard becuase you've probably had to spread the ears of the collar to get the old rack off.
Then you carefully weasel the rack back into place and fit the lines. I had better luck undoing one of the PS lines where it switches from metal to rubber to go to the pump, connecting the hard line to the rack, then reconnecting the rubber line. It was the only way I could get things oriented properly.
You'll need to flush and bleed the system too. You'll have to flush the pump BEFORE you hook it up to the rack or any nastiness in the pump fluid will get into your nice new rack. You can do that by pouring fresh fluid in the top while either cranking the motor with the coil wire undone or by rotating the pulley by hand. Do NOT overtighten the fluid lines, and do NOT cross thread them, which is easy to do because the fittings are brass and the housing is soft aluminum.
That's about it. Good luck....