I just finished the Z32 26mm front brake swap on my S14, and I do have to say that it was pretty easy. On a scale from 1to10 I would give it about 3.
Some things to keep in mind.
A, its messy, so have rags/newspaper/etc for the brake fluid.
B. Cut off wheel is a must, as the dust shields have to be cut (in my case cut off)
C. You need 2 people to bleed the brakes OR speed bleeders.

Now for 5 lug people, S14SE wheels clear 26mm brakes, and I am told that will clear 30mm ones too, but I got the 26mm ones so I can verify those, but supposedly these are the same as S14 in Japan where they came with the 4 piston brakes.
SOME S13 alloy wheels will clear ONLY 26mm ones, search on FA/Zilvia for pictures to show you if you got the right style wheel (there is 1 that will and 1 that wont).

Getting lines from SPL would be best, they fit great and are pretty much direct swap for the stock brake line. They even fit into the OEM clips.
Tools needed:
19mm socket (hold the caliper)
7/16 and 9/16 wrenches (for SS line fittings)
10mm socket (wrench (bleeder screw)
12mm socket (line bracket)
Cut-off wheel (cut the dust shields)
Brake fluid
Brake Parts cleaner
Rags
Antisieze
I would also suggest using some kind of tube to put on the bleeder to have the fluid go directly into a pan/canister etc. Otherwise it can get a little messy.

install itself is very simple, and pretty fast. 2-4hrs depending on how fast you work, maybe less. I was doing a lot of goofing off and explaining everything to the missus so it took us a little longer.

As far as the shields, you can remove the lip or as much of it as you can, I cut mine up almost completely off. *I took them completely off from the spindles I will be using in S13.*

Due to different size of Master Cylinders on the S- and Z-chassis there seems to be a lot of talk about the brake pedal feel, I payed special attention to the feel/height/stiffness of it for about a week now, and on my way to the meet, I drove a little bit more aggressively and I managed to get my S14 to have pretty bad brake fade.
After the install of Z32 brakes, doing pretty extensive bleeding (wanted to get most of the old fluid out) and proper brake break-in procedure, the pedal feel is the SAME, pedal height is the SAME, and the pedal stiffness is the SAME as stock S14 single piston caliper brakes. Stopping seem to have improved, but since my S14 pads were pretty much in a DIRE need of a replacement, and are probably a POS autozone special, I cannot compare them to the MetalMaster brake pads I have now as far as distance, and I haven't measured the 60-0.
This is all done WITHOUT the Z32 master cylinder.
I will post an update later on when I do Z32 on all four corners on the S13, without a Z32 MC.
Keep in mind, I used 26mm brakes, new pads/rotors. It may differ if you are going with 30mm.

So if you are thinking about getting the Z32, I would strongly suggest it.
the calipers are about 110 bucks new at autozone, lines are 45 at SPL, all required Z32 brake caliper hardware is 25 shipped from Nissan, than just add the brake pads/rotors of your choice and you've got great system.

PS. I heard that Nopi has killer deal on brakes, (Z rotors for under 25? IIRC)