Anti-sway bars can be picked up from ADDCO , 7/8 front 5/8 rear.
A 280ZX strut will fit but you will need the control arms and radius rods. The problem you will face is if you lower the car more than an inch or two you will need to flair the fenders. I would just put the coil over kit on e-bay. coil overs are fine for us racer types but unless you have access to scales you can actually screw up the handling with coil overs. The 240Z rear springs in the front work well.
I still have the leafs in back but they are the NISMO ones and don't suffer the pick up truck chatter over wash board surfaces.
As for brakes Wilwood makes a caliper called the Dynalite (twin and 4 piston) , these will fit over the standard rotor. You will have to make a mounting plate. I used Dynalites on a single seat D-sports racer I had a few years back. (The car used VW Scirrocco uprights) The vented ZX rotors are nice on my 1200 but the calipers had to be milled to fit inside a 13" wheel plus I use a wheel spacer.
Ball joints can still be had from a good parts store , although I use all rod ends and spherical bearings so my knowledge of ordering them is at least 5 yrs old.
One day I still would like to have a strictly street 1200. I plan on running the Addco bars , Wilwood calipers , 240Z spings with tokico inserts , Nismo rear springs and a set of 185/60 13's. Motor would be A14 with header and 32/36 weber. Throw in some nice period Recaro seats. This should result in a car fast enough to have fun with but mellow enough to keep La Policia concentrating on all those decked out Civics they love to pull over.

Tom