This install is rated a 5 out of 10 on a difficulty scale.  List of req'd tools for this install: torque wrench, floor jack, two jack stands, wheel chocks, a set of EXTERNAL spring compressors (available as a loaner from many auto parts stores) a comprehensive set of sockets in both 3/8" and 1/2" if at all possible, and finally some WD-40.

Now, let's get started on the install.  First, hose down all the control arm bolts, lower shock retaining bolts, and spring retaining clip bolts with WD-40.  There is one concept to keep in mind: in order to make this as easy as possible, use the floor jack to compress the springs rather than the spring compressor.  In other terms, your spring compressor is going to be used as a "compressed spring holder" instead. 

1) Clean the Jeep's entire axle area (especially the lower control arm mounts and shock absorbers) with a pressure washer before you begin.  This is good advice for ANY install.  You have less gunk to work around, less gunk on your hands, and less gunk in your eyes.

2) Begin by chocking all wheels, both front and rear, so that the Jeep doesn't roll.  Make sure it's in PARK with the Emergency Hand Brake applied tightly.  Let's start on the front.  Remove the upper 15mm nuts (WJ is 18MM) from the sway bar end links on both sides of the Jeep and swing the sway bar up and out of the way using a bungee cord if necessary.  Make note of the orientation of the swaybar endlink bushings and the order in which they go on, and then set them in a safe place.

3) Starting with the passenger side front, insert the jack under the axle tube as close to the outside as possible, and begin lifting the jack until it touches the axle tube.  Do not remove, but loosen the lug nuts about 1/4 turn while the tire is still on the ground. 

4) Jack up the jack so that the tire clears the ground.  Safety First: Place a jack stand under the passenger side axle tube AND under the frame rail just behind the lower control arm on the passenger side, and then remove the lug nuts on that wheel.  Remove the wheel, then take loose the bolt that holds the spring retaining clip, and lastly the lower shock mount bolts.  They should be 13mm. 

5) Put the spring compressors on the spring, making certain that they are on opposite sides of the spring from each other.  If they are clocked too close together, they will move toward each other when the spring decompresses, and will likely injure you.  Tighten down the threads by hand until they are hand-tight.

5) Now, begin lifting the axle with the jack. Tighten down the coil spring compressors again.  Make sure that the opposite side of the axle is still firmly planted on the ground before doing anything else, and let the jack down a little if it's not.

6) Without getting under the Jeep, reach your arms down to the jack stand that's rearward of the frame lower control mount and lift it upward so that they are up as high as it can be, making sure that it's not extended upward far enough to make the jack stand unstable.  Your jack stand will need to stand firm at a minimum of 16" extended, more is helpful.

7) Remove the jack stand under the axle tube, and being to let the jack down VERY SLOWLY, allowing the jack stand to catch the weight of the Jeep.  If you see any movement from the coil spring compressors, you'll need to start all over and re-center them.  You can begin to see the spring SLOWLY starting to come loose from the top spring mount.  When it drops down a little over 2", stop the jack from dropping any further, remove the lower spring retainer on the rear inside of the axle's spring perch area with a 12mm socket and remove the coil spring, setting it to the side.  If you find that it won't drop enough, jack it back up and remove one of your control arm bolts, especially if you don't have adjustable control arms and/or rubber bushings.   If your factory bumpstops are in place, pull the rubber bumpstop part out of the steel cup and remove the 12mm bolt that's underneath, or if you have the older style, you can unthread them using a large Channel-Lock or pipe wrench.  Remove the large rubber isolator washer from the upper spring retainer, and put one of the front budget boost spacers over the spring retainer post, and then slide the large rubber isolator washer back over the post, sandwiching the spacer.  If you purchased front bump stop extensions, get out your drill and mark the center of the hole to put the bumpstop extension on the lower side of the axle's spring perch.  Now, replace the coil spring.  You may elect to use the spring retainer clamp at the bottom of the spring to hold it in place when lifting it back into place.

8) Slowly lift the jack so that the axle brings the coil spring back upwards.  As soon as it seats correctly, you can jack the Jeep back up to the position it was in earlier and can slide the jack stand back to the position it was in at step 4.  Loosen the threads on the spring compressor and remove it if it's easy to do so.  If not, just loosen the threads until they are back in the same position as step 5.

9) Release the pressure from the jack, allowing the spring to decompress, stopping when the axle is in a position to replace the lower shock mount bolts and the spring retaining bolt.  Also, replace the wheel and tighten down the lug nuts to around 30lb/ft. torque.

10) After the wheel is back on the ground, tighten it down to the recommended torque specification in an alternating pattern (like drawing a star, and somewhere around 95lb/ft.)

11) Repeat steps 3-10 until all the four coil springs have spacers on the TJ and ZJ, or just the front two on the XJ.  On the ZJ, the rear spacer should go between the rubber isolator and the body of the Jeep unless you are installing the Post Extensions.  If you do, then go body>stock rubber isolator>post extension>budget boost spacer>spring, in order, from the top down.  The fit is tight...just put the weight of the Jeep down on the isolator and it will slide over the poly spacer.  If you did not purchase the Spring Post-Extensions for the rear spring posts, you may notice a small amount of lateral slop when you place the spacer over the post.  Not to worry...all of the forces are up/down, and you should get no noise or movement once the spring is re-installed.  If you DID purchase the Spring Post-Extensions (which I recommend doing, since the post is really not all that long, and the SPEs are reasonably inexpensive, simply coat the inside upper 2" with some Perma-tex silicone and slide them onto your existing rear spring post.  These post extensions simply "guide" the spring upward and downward and there is no pressure on them other than gravity upon their own weight, so silicone is a good choice.  You can also elect to use a sheet metal screw through them, into the stock spring post, or a more permanent solution of tack-welding them on.

12) If you ordered rear bump stop extensions, remove the rear bump stop rubber bumpers from the steel cups that they are captured in, remove the two bolts on the underside that hold the steel cups to the frame rail, insert the steel spacer block that came in the kit, and re-install using the new longer bolts.

13) Recheck all your bolts that you removed for tightness, including a final check of all lug nuts with the torque wrench.

Trail testing time.  That's the great thing about these Jeep modifications...the testing is always a good time!  Enjoy your newly found height!!!!