This is going to be a simple How To for the H&R wheel spacer on the rear. When you do get a spacer, make sure it is hub centric and not the ones where there is lug nuts on it. Get one similar to the picture below.
This picture here shows most all the tools you will need to install a 20mm spacer. If you are installing a 10mm or a 5mm spacer then you can probably ignore the stud removal and install.
First jack up the car in the rear and take off the wheels. I did this one wheel at a time. First loosen this bolt on the caliper. There is another at the bottom that you will have to take out too.
Once you get the two bolts off, get the rubber mallet and hammer this part of the caliper off. It should come off with ease as shown below. In the pic below you can see the brake pads and the metal cover that goes on the pads. DO NOT BEND THE METAL COVER. It easily bends.
Next remove this bolt and the one below to remove the second part of the caliper. Once you remove these two bolts, The 2nd part of the caliper comes off easily.
Next the rotor should come right off. It may take a bit of a tug or a few hits with the rubber mallet. DO NOT HIT THE ROTOR WITH THE METAL HAMMER. You can break this if you do.
Next with the metal hammer, knock out the studs. After a good hit they should pop right out.
This next pic shows the studs removed and the difference in the size of studs if you get spacers bigger than 10mm.
The pic below show the rotor cover that has to be knocked back to fit the studs in. This was the only way I could get the studs in. You may try to give it a shot, but after about 30 mins you will resort to this I promise.
Put the new provided studs from H&R in and put on the rotor
Now put the wheel spacer on as such and put 2-4 washers on each stud and the lug nut. This will tighten the the studs into the holes better.
Once you have the 2-4 washers on and the lug, tighten that lug up a bit until you can not push the stud out no more with a good amount of force so when you put on the wheel they will not pop out.
Here is fellow maxima owner Cullen Jones helping me out putting on the wheel.
You really have to tighten up the lug nuts to ensure that they are forced into their holes well. I would tighten a little bit beyond torque specs and loosen and retighten a few times. Be sure to check the tightness for the next few days.
Here are some pics before the spacers in the rear.
Here are a couple of after the spacer has been installed.
And a comparison between two 2002 Maximas. Notice the huge difference.