What are my options

ST's or Eibach's, with Bilstein, or Koni's are the best solutions for OEM style application. Otherwise yes, go all out, and do coils!

Because this is a big decision for me as I don't know what way I am going with the car yet I think the shocks will be one of the last concerns with the car I address. There are numerous small things that need attention that I think I will move to for now this way I can think on it and make a decision I am happy with.

I think I am going to start a new thread based on my plans / goal for the car and go from there

What konis and st's are you running? Just got a 89 zx and im thinking of that setup.

Suspension Techniques no longer sell the coveted ST lowering springs for the Z31, you will have to find them used. Expect to pay $200-300 a set.

Koni sport struts and shocks are adjustable and are still available but expensive.

Honestly koni yellows are the best you can get for the car, and will work with spring rates higher than any available (so if you chose to go custom springs or find another application…)

Illuminas had serious quality control issues in the last several years, leading to the loss of their distributors, which they've only managed to sort out recently… only "good" up to about 250# springs, after that they tend to suffer and blow

Bilsteins are also quality struts but have no adjustability

I would not spend any money on a used set of OEM shocks/struts. IMO, they do not last very long when new and were way too expensive for the low quality/reliability of them. Over the almost 300K miles I had put on the OEM setup on my 85T, I had to replace them all 4 times. It makes me puke to think how much I spent on the OEM setup over those 20 years, like maybe over $12K?

I was like the original poster back in 2005, wanting to keep it 100% stock, until they became NLA. So I selected a replacement set of KYB's.

IMO, the cost, reliability, and because they are NLA, I would just bite the bullet and go to the replacement option. Even if they were still available, the costs is staggering for a 31 year old car.

the car will be getting stance coilovers unless someone can convince me that the powertrix are worth the extra couple hundred dollars

I wonder if I can get something setup so that I can adjust the dampening from the factory switch. I know that tien makes a setup to adjust coilovers from inside the car but I want to use the oem switch

Don't listen to these nerds. If you can get a bunch of used rear dampers for less than $100, and get 3 working ones, why wouldn't you do it? The fronts are easily repairable, and I'm sure regular shock oil works just fine. If you take a rear shock, and compress it, it should return on it's own if it still has a charge. Not rocket science and takes like 20min to swap out a blown one.

If you get coilovers, you will need to upgrade tires and wheels.

You could also get bags. Use the original switch for "subterranean", "normal", and "flyin' over speedbumps".

The factory system has stepper motors and sensors to verify they are where they need to be. Pretty impossible to retrofit anything. Tein thingy is crazy expensive and kinda dumb.

I am no stranger to coilovers and actually really like them. The reason I was against it at first is that I want to keep the car totally factory but now I am ok with the car not having oem dampers. I can not justify the cost of a quality spring strut combo when coilovers are not much more and I like them better

I did not know that you could repair the fronts can you share the information on how to rebuild them because if I can get the fronts repaired I may buy some used rears

Pretty standard setup, really - Koni Yellows paired with front ST springs and Mach 1 rear springs. It's not my first nor last setup on this car, but it's a decent ride for the [minimal] money spent: less than $500 overall.

Bushings and tires will also make a drastic difference in how it rides and handles. So keep that in mind.

I have a set of front only ST's and would like to pair them with something for the back. Are these Mach 1 rear springs low enough to match the ST fronts? if so, what year Mach 1 and what brand if not Ford OEM

From what I've noticed, the front sits just a bit lower than the rear on turbo cars. I only had pictures of frostvectron's NA to compare to when I got mine - it sat fairly level. More weight on the nose of a turbo car, though. Its not enough to bother with how little the car gets driven. A cut coil or finding some aftermarket mustang springs with a subtle drop would probably cover the 1/4" difference.

The springs are OEM Ford 2003-2004 Mach 1 rear springs. They have a 250# rate versus the ST 226# rate. There are a few threads on here that talk about using Mustang springs for reference.

What if someone did an air ride suspension- could that be the closest solution to the oem adjustable shocks?

Air suspension isn't as stiff, but also soaks up small imperfections better than any rigid bodied fluid strut

In short they are very different in feel